Yeah as a general rule when I post I am talking to or in regards to the original poster who is from Stillwater, OK. Susi´s trainer appears to be from Germany or some other European country. My point was that I see no need for neutering a male if you do not have a law requiring you to do so. Keeping a male by itself between breeding is not, in my humble opinion, abusive.
In order to recommend how many and what size breeding groups we would need to know how many snakes you have, what size they should be eating, and whether or not they will take F/T.
If they will take F/T then breeding rats and freezing them when they hit weight is a great option as you can let them grow bigger as your snakes grow.
Mice and more so males use urine to mark territory so a litter box will only get you so far. I find that with a large group they will tend to use a particular corner or their tub. I spot clean that corner every other day and put down some baking soda to absorb the oder and cover that with bedding from the center of the tub and then put a hand full of fresh bedding in the center.
When i do a full substrate change for my BP I will reuse that aspen cut with 50 new aspen for my mice. I don't have issues with water bowls spilling and I spot clean constantly so the bedding I take out of the snake enclosure is just like new. If soiled at all its soiled from the feeder mice that have been in the cage and even then less so than after a single day in a mouse tub.
Stinky is a relative term. Using all of the techniques singingtothewheat suggested as well as spot cleaning between full litter changes I still find a mouse tub stinks a lot more after 3 days than my pet gerbils cage after 3 weeks. Whatever you do the easiest advice to follow that will make the most impact is feeding your males before your feed your females. Adult females are easier to deal with than adult males.