Hi Chris,
I've not seen much out there on Double Green paper. What I do see usually says heavy hand, or cracks. If you do a search on Double Green, you will see what I mean. In all fairness, I can only say what I see out on the boards. But I wouldn't buy double green for shirts myself.
Not when there is a paper like Jetpro Sofstretch on the market.
JPSS (jetprosofstretch) is about as great as it gets for shirts. Soft hand, colorfast, can work with various inks. I bleach my shirts many times in wash tests, they look great.
Here's some pics:
Wow! Jetprosofstretch JPSS & Bleach Results -pictures - Canon Dye ink and Durabrite Pigment ink
Not many papers are going to hold up to that, and none that I've heard of being bleached. I like tshirtsupplies.com and New Milford Photo as suppliers. You can google for more, price varies, and make sure to sign up for newsletters with everyone so you know who is having a sale when. Tshirtsupplies.com is offering another 5% off their low prices for signing up for the newletter. New Milford Photo has been known to hold awesome sales. Good luck to you and ....
Advise on SofStretch vs. Double Green 
