It surprises me that there is not more information about womas available. They are becoming pretty popular.
While I don't have a "care sheet", I will be happy to review the highlights of how I keep mine, and maybe some of the others will chime in.
First, womas are a very hardy snake that thrive in a range of conditions in the wild. As a result, they are tolerant of a relatively wide range of conditions in captivity. That said, most keepers, including myelf tend to keep them on the dry and warm side. I have never misted my womas and do nothing to raise the humidity. For temps, I keep the basking spot in 90'ish range for most of the year with the cool side of the cage dropping into the low 80's.
For caging - I keep adults in 4' x 2' cages (most are either 15" or 18" high). Some of the smaller adults can be kept in 3 x 2 cages. For hatchlings thru juvi womas I keep them in racks with tubs based on their size. For the first few months I keep them in a relatively tight space but as they age I make sure the tub is big enough to give them plenty of room to move.
For decorations, I have some cages with basking shelves that are used often, but there is no need to add perches or branches. I keep a water bowl in the cage and a hide that is large enough for the snake to get in, but should be fairly snug. I also tend to prefer top entry hides for womas.
Substrate is up to you. They do fine on paper towels, newsprint, contractor paper, care fresh, aspen and many people (esp in OZ) keep them on gravel.
They are rarely problematic when it comes to dinner time. They usually have a strong feeding response. You will need to monitor the feeding of your adult as they will become obese easily and this can result in liver issues.
Due to the feeding response - you will need to be careful when you initiate contact with them. You want to make sure they know it is handling time and not dinner time.
Also, there is a long running debate on the importance of feeding frozen/thaw rodents to snakes. With womas, it is especially important. They are messy eaters and sometimes won't constrict like most pythons. As a result, a woma feeding on live rodents will become scared - and possibly worse.
As for your troubles finding average size - there is a reason you are finding conflicting information - there is a large variance in adult sizes. I have seen adult females less then 5' and some in the 8' range.