I print blends and especially tri-blends all day with soft hand plastisol on darks through middlin mesh counts. Sell the idea of letting the striations of the fabric show through for a "vintage" look.
Honestly, I doubt we could print any softer on these with wb, maybe with super pigmented discharge after laundering, but with the softee inks it's one hit crap. No double underbase to deal with.
Getting a soft hand and super opaque ink film is a juxtaposition with these garments, they're just too rough on the surface and you can't discharge the poly completely.