i am all abo now. i use all antler tine flaking and actuall after getting used to it i like it more. i have different sizes for different thickness stone. 
i have large tines i use like an ishi stick. it has 2 branches one is 1/4 inch diameter at tip. the other is a little over an 1/8 inch. ( i sharpen them alot to keep that diameter.
my one that fits in my hand i sharpen to resemble a pencil tip. for finish edge work. 
prep of platform is all important as explained by jamie. 
with antler i sometimes push so hard i think i am gonna get an aneurysm. usually resulting in a beautiful flake scar. 
