What would you DIYers suggest...

I plan to convert this I picked up on e-bay into a kilt pin:



It is just shy of 4" long and was planning to mount it like this (inspiration and photo from The Kilted Reverend):



Two problems I see are:
1. curvature of antler tine
2. height difference between tine and arrowhead

I thought I could sand down the tine to make it even with the arrowhead but I am afraid it would affect the mounting between the two pieces and loosen the arrowhead from the tine.

So I thought I could use Tie tack backings (2 or 3) instead or a small 3/4 bar backing on the tine combined with a tie tack backing on the arrowhead.





Has anyone used the tie tack backings? with success?