I think the straighter, longest layer needs to basically be hardly longer than the bit that lies on top of it. You can have a tiny bit hanging down, but so little that it won't show that it doesn't wave or curl like the rest. It may wave up a bit more as it is cut shorter though. Because it is less wavy it won't bulk out the bits overlying it too much. Probably, I'm no expert! Then your wavy layer over that, then the topmost/curly layer not taken too short as it will spring up more. Show the stylist the difference in spring factor on your hair, also you could take some pics that are typical to reinforce the point.
UK based wavy

Mostly waves, but curls and straight bits too!
Fine to medium, high porosity, medium density, very low elasticity
Highlights damage (growing it out), seems to like protein and need lots of moisture.

Cleanse - CJDF, trying out low poos ; Co wash- Uk chemist brands, Urtekram Rose or Aloe, Hairveda Amala Cream Rinse; RO - varies, Tigi Moisture Maniac, Desert Essence Coconut ; Leave in - Keracare natural textures; Sealant - argan oil
Trying out new things, still looking.