Tubs are a great option. Personally I prefer the Iris brand because you get all the benefits of a tub but they are also glass clear. They aren't as easy to find as Rubbermaid or Sterlite but usually all the major office places have them (OfficeMax, etc.) as well as Bed, Bath & Beyond and some Targets. They also have the benefit of being totally smooth inside and once you've chipped some rock hard urates from a tub that isn't smooth, you'll get why that is so important. All tubs require supplimentary security though. Any give and you've got a loose snake. Things like large binder clips, C clamps, bungee cords work very well.

If you are the handy sort, you could also build a very easy two tub rack and avoid the whole lid escape issue altogether. There's tons of rack plans here.

As far as the snakes I would get your enclosures set up and dialed in first if possible. I would go with a pure white paper towel layer substrate so you can watch for mites or even do a preventative mite treatment since they may have a history of poor husbandry. I would place the snakes in a very quiet part of your home and leave them for at least 1 or 2 weeks with no interactions other than basic cage sanitary care. No handling, no attempts to feed. Just provide a quiet, appropriate home and fresh water and call it good for the first couple of weeks.

After that time I would focus on getting them feeding regularily. Then I'd worry about issues of handling.

It wouldn't be a bad thing to do fecal floats on both snakes. Again, because of information about possibly poor care that's a smart and relatively inexpensive thing to do.