Lots of great advice here. It will be your kilt, so should be the style you prefer and find most comfortable. Your kiltmaker will be able to accommodate your preferences, as the kiltmakers here have said, so working closely with her/him if key.

On straps, I'll be contrarian - I prefer two straps but it's the left inner apron strap I'm happy to lose, military style but that's a personal choice. I hope I've not put the cat among the pigeons!