Okay guitar gang, these days it is getting more and more common for us guitar players to be forced to play direct and hear yourself ONLY through the ear-buds. Wow, that takes some time getting used to. And so ...
My first suggestion:
Whatever buds you ultimately end up using, spend a ton of time playing your guitar and your guitar with backing tracks using the in-ears. This way, you will already be ahead of the game by being comfortable and confident with the tone of the in-ears.
My second suggestion:
If you can afford it, (or the tour is paying for it) DEFINITELY have a set molded to fit you exactly by the best of the best: Ultimate Ears , they litterally INVENTED the concept, and for better or worse, in-ears may have NEVER became a thing without this company!
A side-note here, a few years back I was fitted by UE, and I found that the UE 4 Pros were no better than my cheapos! Until you shell out for the UE 6 Pro ($699), you are NOT in real fully pro in-ear monitoring land, and realistically, to get the real "UE" experience, you need to be at UE 11 Pro ($1,199) or higher. For MOST of us, we really can't go the UE route unless we catach a tour that pays up for em. So....
My third suggestion: (This is what you want to hear)
Get some inexpensive in-ears that still sound VERY good! Duh, right? I can save ya some time here; I started playing through "ears" well over a decade ago and I've been through very nearly 100 sets of buds, including the afore mentioned UE 11 Pros and every model Shure has ever offered. And until I got the UE 11 Pros, I was always disappointed, and more money definitely did NOT equal better sound or more comfortable fit! Ugg. However, I did have one set recommended to me that actually sounded REALLY good, I'm talking nothing below $500 can touch it good. The model is the 6-driver KZ ZS10 Pro, clocking in at an amazing fifty bucks! I was playing at a Nashville area mega-church and EVERYONE in the band swore by them, the leader then gifted me with a set, and ... wow! I now use these for almost all in-ear gigs that don't pay big bucks because the UE 11s are just too darn valuable to take a chance something might happen to them.
How good are the KZ ZS10 Pros? Honestly better than EVERYTHING I have tried before except for the UEs. They do NOT come in any flesh colored options, so it's going to look like you have in-ears in; I like that, the flesh colored ones look like hearing aids! Check them out on Amazon here: KZ ZS10 Pro