Yes, you can dial in more advance with a bit richer mixture. Remember though that some of the extrea advance is just to counter the slower burning rate of the richer mixture and doesn't necessarily make that much extra power as expected. Depending on everything obviously....
Also, moving advance around will slightly change the fuelling too. So, it's an everything affects everything scenario as usual.

Remember that with turbo cars the relation between power, efficiency, CR/cams, turbo size, mixture, boost and advance is never straight forward. You need to decide what you want out of it and whether it's an everyday year-round car or a track-day toy.