Attaching antlers to plaque

I'm want to mount my elk antlers and skull cap to a wood plaque.
What is the best way to attach it ?

I have a Rinehart solid wood plaque (walnut)13" X 13" X 1"
Should I use wood screws through the skull cap into the wood, or drill through both and use metal screws with nuts and washers on the back ?

Should I use some type of soft nylon or rubber washer against the skull cap to protect from the bone cracking ?

What I usually do is pre drill the plaque and just use some gold deck screws into the skull plate, making sure they dont go through the skull plate. That way you dont see any screws and it looks a little cleaner. If you have a plaque that is fairly hard wood you should have no problems with it holding, just make sure you use long enough screws to get a good hold into the skull.