So uhhh... I'm not sure where you got the idea that there was no CTM support for these...

Just put this on top of continuity's CTM, and boom, basic slab CTM.

glass_slab.properties

matchBlocks=mo_glass:glass_slab:type=bottom,top
tiles=0-46
connect=block
faces=top, bottom
resourceCondition=textures/block/glass.png

There's a little bit of jank with double slabs, but CTM does work with both slabs and stairs. If you don't believe me, I will make a PR to prove it.
Stairs will require many, many properties files...