I use gold-tip carbon arrows, Mathews FX ~64lb's, and so far thunderhead 100 grain tips. I plan on trying the muzzy mx tips this fall.

I need to get new fletching, was wondering if a 1 1/2" or 2" would be better then my 3" I am using now.

Btw, my rest is regular shoot thru, cock feather down.

i use the two inch blazers on my goldtips, and i shoot the mx-3s, i haven't hunted with them yet, but so far, target shooting im impressed with how well they spin and how accurate they are. i've had feild point accuracy out to 40 yds with them. you'll be hard pressed to find a better head than the mx3 or mx4. in your setup i figure the 2" or 1 1/2" would probably hold up better, if your experiencing fletching damage, but if your 3 inchers worked well before i wouldn't change, "if its not broke why fix it"

2"Blazers from Bohningare made for broadheads
1.5" is made for target shooting with field tips. It states that on their site.

The only way I would consider smaller vanes would be with mechanicals and even then I just don't know. You may have stability issues and there really is no benefit to using the smaller vanes for hunting.