Based on this range answer of play top 70% against 100% it got me thinking.
Pre your opponent will open or call 3x with any hand.
Your choice is to open 3x, call 3x, or fold.
Clearly you can play top 50% and be ahead or tied with his range.
Since you have a blind to forfeit it seems like you would play more than top 50%. And would probably vary in SB or BB.
Can assume it gets checked down after that. Or you can make other assumptions but please state them.