I have found that shooting these sort of bows (I've made lighter ones) you don't really need a mark after a while. The arrows will leave a little mark and also as you get used to the bow you will change hand and nock position to where it feels best. When I'm shooting them in I don't even use a marked nocking point I just go by what looks right.
So far this bow has been great to shoot, especially with the heavier arrow I made. The tips are still about 1.5" behind the handle with the set very even. The next one will definately be at least 4" longer, maybe more. I have at least one rediculously larget piece that would make a 7' bow 2" wide! I'll save that for last.
Now all I need is to find some horn for nocks, although not until I get up to a weight that requires them.
Cheers,
Grant