I’m not a clinic leader or examiner so this is just another viewpoint.
My experience has been the examiners are looking at skill blend and movement more so than is there a skid or curve. While they may ask to see either, none of the exams I’ve taken have been that specific. They only asked us to ski a pattern on one foot.
If you can carve on one foot you should also be able to skid. The difference is how you blend the skills, mostly edge and rotary. Practice both.
You should be doing things like lane changes and hour glasses (large radius to small radius to large radius). Practice these on two feet and on one foot. Changing radius will promote steering and skidding as well as carving.
I added skiing the bumps on one foot. But if you do start small and be careful. The objective is to be more versatile in your skiing, not break legs or knees.
You mentioned working on green and blue. Add black to the mix. You may not have the control you expect or want (I never have) but it will challenge you. Even if you only get a couple turns done before getting the other foot down, when you take it back to the blues you’ll see an improvement.
I hope these spark some thoughts of your own. Good luck with level 3.