First, it'd be a good idea to layer the top of the bamboo boosters with micro fleece. This wicks the moisture away from the skin. With out the wee does sit against bub's skin.

An idea is to have micro fibre or something on top of the bamboo as even though bamboo holds alot, it is kind of slow to absorb, so the micro fibre would absorb quickly while the bamboo absorbs underneath slightly slower iykwim.

I think it'd work out cheaper. IME a half metre of bamboo fleece I got on ebay for $10 layered 2 - 4 times depending on how thick you need it will go a good distance. Depending on the size of them etc.

Personally, I've had bamboo against DS's skin (not good for him though), but I'd never put micro fibre against his skin. My DS is quite sensitive, so when making my own I have a heavier weight micro fleece against his skin & try to avoid having less than double layers of microfleece. Mainly over night. I use microfleece liners too.

I prefer bamboo. Its softer. Thats my only reason.