I made a cardboard wing and and mounts to test the different options. With the 93mm mounts the wing is right in the top 2/3 of the rear view mirror. With the 230mm mounts I couldn't see the wing at all.
Worst case scenario, the very top of the rear view mirror is gonna obstructed by the wing. So this is good.
Shinoo said he didn't sell any wing with the tall mounts yet. I'll be the first! The taller mounts give more DF with less drag. The penalty is more rear bias. So I'll probably just run with less AoA until I get canards or add more rake.
In any case, having some understeer in the fast sweeper is not "bad". In fact, most time trialers I know actually run faster in cars with high speed understeer.