I use coco husk for snakes that require more humidity. I like it, however because when damp it will stick to everything, I would likely feed your BP out of the enclosure so he doesn't eat some of it with the rodent.

Cypress mulch is good, you just have to be careful where you get it from. I've even had the ones you get in the reptile section have broken glass in it. So I always go through the substrate no matter what it is.

I can't comment on orchid bark as I've never used it, or seen it for that matter.

I get the teklad lab grade Aspen and the exo Terra Coco husk bricks. For the Aspen I pull it out of the bag and uh I don't know the word I'm thinking of, I guess I sort through it then place it in the bin. For the Coco husk I make it up in a big bucket, then I grab and place in the bin while combing through it. I do a brick at a time and that way it has time to dry.

I'm just picky about having things ready and organized though.