What is the scoring format?
If it's medal play, I think the best plan is to just allow players with a handicap over a certain number to play all 9 holes from the green tees. It's much easier to convert their handicap that way to make scoring equitable - just adjust their number to the reduced slope and rating.
If it's match play, you could do the same, but you might also be able to get creative. Personally, I'd think about putting in a rule allowing the higher handicap player to scoot up a tee on any hole they get a stroke on, but they must give up the stroke to do so. Then, you could even allow the lower handicap player to "press," enabling them to play from the next tee up as well but return the stroke to the competitor. You'd get some interesting decisions that way and increase the variety of the course from week to week as players could play potentially play different tees on different holes. It's admittedly a bit tougher to handicap, but it shouldn't be too hard to calculate.