One of the most difficult things about lighter switch and spey rods (and indeed for two handed rods in general) is finding and dialing in adequate lines to match them. Overhead lines are one thing but lines for two handed casts are another all together. There is definitely a limited availability of lines, and even less people selling them with any clue as to what works. Even if you fish heads, they still cost 50-65 bucks each retail, and buying five of them to find one that works is a frustrating and unrealistic process.
Very generally most true 4 wt trout switches that I have run into are going to match up with either a 240 or 270 grain airflo compact scandi, but what if you hate scandi’s and want skagits? Somewhere between a 250-320 grain skagit is going to generally match up quite well. Hate skagits? What about mid or longer bellies? Things get even more tricky from there.
First of all what you need to do is really think about what you want to use or even need a trout switch or spey rod for. Do you really need or want one? Is it just a light summer steelhead rod? Is it primarily for chasing average sized trout? Big husky river browns and bows? Sea runs off the beach? Are you fishing deeper, cold water for coastal anadromous fish, stripping streamers or fishing warmer shallow water for wary small resident trout? Are you fishing far and fine and mending a lot? Nymphing? No one line or rod necessarily works well for all of these things. There are places and situations where these rods are probably more of a hindrance than a help. Before you even begin looking for a rod, think about where you want or need a trout rated switch rod. Then how long a rod do you need? If you fish small rivers that are 20 ft across or less, you are probably going to wish you brought a single hander instead. 10’6 is still pretty long if you are stripping flies or fishing small water. Your specific rivers and setting in mind, not far flung places you may never see, or places you don’t fish often, will give you the best idea of where to start. Figuring out what your preferences are is also key, especially what you like about other rods, eg. loading the rod deep, or casting off the tip. What is the action of the rod you have or are going to buy. You need to think about these things, not just plunk down a bunch of cash on a trout spey, and then expect to be casting 100′ with perfect loops.
If you have little experience with spey casting, then learning on a light switch rod is going to probably be quite difficult.
Switch lines: Snowbee switch (floating and intermediate) lines (to 200 gr.), Wulff ambush lines, and the Rio switch chucker (to 325 gr.) are all good choices for shorter switches. The Rio switch line only goes down to 375 gr. @ 55 ft making it useless for trout speys. They are general purpose short, beer can like fat lines with short tapers, similar to skagits but with more taper, typically they are poor for mending, delicate presentation and nymphing.
Skagits: Rio (skagit short to 250 gr. ,skagit max short and ishort to 200 gr.), Beulah (Tonic 300-325 gr), Scientific anglers skagit extreme( down to 280 gr.)(Airflo’s skagits only go as low as 360 grains which takes them into 5 wt territory) and probably others now all make light skagit or super short shooting head style heads some of them going down to around 200 grains these are probably the easiest to find of all light trout lines.
Scandinavian style heads: Vision (Vibe 65 a 21 ft scandi style integrated line down to 92 grains! designed for single hand rods, but will work nicely with shorter rods and conversions) Airflo compact scandi(240 gr-270 gr @ 29 ft), rio scandi body (down to 210 grains @ 23 ft), Beulah elixir (down to 245 gr grains @ 25 ft) These lines work very well as a general trout line but are usually fairly short heads and therefore poor for mending.
Mid and Long Bellies: At this point if you want to delve into this world you are going to have to do your homework, try different single handed lines, (different sized double tapers are a good start) maybe chop some lines or get a custom linemaker (Steve Godshall in Oregon my friends) to make you a line. There is simply no commercial interest in this at this time. I know a lot of people covet the 4/5 GPS lines but they are actually heavier than what most real trout rods can handle. Whatever you do, there is no easy out of the box line commercially available.
The first line I got with my first trout switch rod (a Beulah classic 10’6 4/5) was a 245 gr elixir scandi switch head. This line is recommended and designed for this rod. It was and is the worst line I have cast on that rod to date, now this is my own subjective experience and yet I’ve heard of similar complaints from others using lighter rods. You have to try these lines, not overhead but in wind on the water casting.
The best things you can do to match a line to your new switch or spey rod
1. Try other people’s, tackle shop guy’s, whoever’s lines on your rod at the river. Do this with rods too. Before you buy. Try as many lines as you can, DO NOT just compromise and buy what is immediately available at the shop. Try them with different leaders and different sized and weighted flies
2.Ask for advice on: two handed trout, skagitmaster forum or speypagesor other online resource, email people who post about these rods and see what they have to say. Do this before you buy.
3.Take all these things into consideration. You honestly have to love trout fishing to enjoy these rods. If you are casual about it and only really love steelhead and salmon then this stuff will probably not interest you. Don’t buy these rods if you feel kind of indifferent to the whole thing, save yourself the headache and hassle. It’s easy to read a bunch of articles and then get all pumped up about buying a bunch of shit. If you love fly fishing for trout, and all this stuff doesn’t scare you off, then proceed down this road.
In the end only you can decide what works and what doesn’t when it comes to lines. Good luck and have fun.