All changes were made with workshop ships in mind - and ship building being optional.

1. Subscribed ships just work with new flight model
2. Buying workshop ships without editing them - is a part of this mod.
3. New Upgrades change stats even if your ship cant fly at all

Just gyro array blocks are replaced with thrusters, so watch out for that when editing/saving ships.
Vanilla ships to Xavorion works fine, but moving a ship from X back to Vanilla may not work.

Excellent! That was my main concern in trying out your mod. Thanks for the clarification!

Any suggested ship collections or ship authors who make designs tailored for Xavorion or who you have found particularly effective in Xavorion when focused on progression?

Havent made a list yet. I'll probably make a personal collection at some point.
It will be attached to main mod page with something like "Recommended Ships".

For now, only my own starter ships up to M4 Corvette, which isnt much.

But, Class System was made to use workshop ships - most of them should just work.