Can Aspen be used for a BRB tub enclosure?

I tried aspen for a while and didn't have any problems humidity wise, but I had a problem with mold. Aspen is not good with the humidity requirements of a baby BRB.

Aspen has a bad tendency to mold really easy. Stick with paper products or cypress mulch for higher humidity enclosures. BRB's need cool temps with high humidity.

so everybody pretty much agrees that aspen molds too easily and doesn't retain enough humidity. I don't want to use Cypress because it holds it to well. Is there a substrate that is in the middle between this two types? I was thinking of getting New Zealand Sphagnum Moss that Zoo Med sells. What do you guys think?