I use reptile bark / orchid bark in 19 of my 20 vivs as part from being fabulous looking substrate the dark colours show off the bright coloured or albino snakes like nothing else around . My MKB is on light coloured beech chips for the same reason .
Reptile bark can be used to adjust the humidity very easily as it can be sprayed regularly or used very dry if required .
I feed in their vivs so I simply lay pieces of card down and drop the d/f mouse / rat on top of the card .