I've done antler tip overlays on the Hazel bark-on bow, they blend in nicely with the bark as long as they aren't cleaned up too white!
The top overlay (left) is a lopsided sliver reflecting the natural twist in the limb rather than trying to fight it.
I found an old Dacron bowstring which gives a rather low brace (4 1/2") but it allows me to shoot it in a bit before final tweaking. I think flatbows can shift a bit as they are shot in so I've left a bit of spare draw weight to play with.
It's 45# at 28" on the low brace. I need my bracer to shoot it as it's a bit of a wrist slapper at that low brace, but it's allowed me to adjust the grip to suit how the bow draws. It's shooting hard and true and I'll be making a proper string so that I can shoot it at the club tomorrow (weather permitting).
The antler is much harder than Waterbuffalo horn, and I've stuck on the thin overlays using high viscosity cyanoacrylate (superglue) for a change. I'd been discussing the merits of various glues with my brother who is moving away from epoxy for some things (he restores shotguns, and some stock repairs require the use of glues).
As I'd had one overlay come adrift on my 'Twister'* bow which had been epoxied I thought I'd try the cyanoacrylate. The pic bottom right shows how the limb tip is rasped back at an angle so the overlay isn't simply flat on the top of the limb, but slightly angled into it.
Update:- I've made a string and shot 50 arrows, it feels very good, still a hint of wrist slap as the brace height is still only 5 1/4".
I'll twist the string a bit and slowly bring it up to somewhere nearer 6" once it's shot in a bit more.
I've shaped the grip a little more and it's shooting very nicely, the grip has the pith line from the centre of the log showing up it's middle, which I like as it shows the origins of the bow.
* I reglued the overlay on Twister and added a silver pin though it into the wood.