It is a bit of a shame that anti-curling methods are pretty much the opposite of high transparency methods but then again, a perfect world would be boring 
I have never had much luck with the “Support” filaments. I had great success with BVOH (after a lot of cursing dialing it in), in particular with PLA but also PETG.
But then I found the PETG for PLA support (and vice versa) thread here in the forum. Tried it out and never looked back.
