O.L. I'm shooting a 125 grain stinger. Yes, they are the MFX and are slightly smaller. I didn't try the lighter heads, and I had built up my strike plate, but all it did was cause a small kick in my flight. Oddly enough, I replaced my rest last night (Neet Pro Rest) and didn't build up the side plate again and I tell you what, I'm getting great flight, some of the best that I have ever had, but to bare shaft the things is weird and isn't making sense. When I decided to go to the 400s, I bare shafted the ICS shafts and all worked out great, but with the Clasics- they don't to cooroperate so I just cut them the same length as the ICS, fletched them up and things are going well, even witht he broadheads. I'm kind of starting to wonder if I just wasn't a little out of wack with the 340s, but they bare shated and flew great. I just wanted to create a set-up where I didn't have 2 1/4 inches hanging over the end of my bow.