@BigDazz Sure if you have no desire to actually culture them, letting them lay/hatch eggs, but will be purchasing waxworms every 2-3 weeks that would work great. I didn't realize you wasn't going to bother with culturing them (eggs/larvae/adults) and will just buy waxworms as needed - that will make matters much easier for you and at which point the only number to worry about is 1-3 weeks for them to emerge as moths, after cocooning.
You would just need to occasionally remove build-ups of webbing/dead moths/excess cocoons/tattered cardboard and add in some fresh food which can be done with the tongs; however, as the waxworms won't be eating much anyway it should be easy maintenance.
The waxworms like angled crevices to build cocoons in/on, so if you use small strips of cardboard (like described in
my article here Step 4) you should be able to add/remove them with tongs too - I would test fit the cardboard pieces to find a ideal size, with your sleeve at 1 1/4" in size you might find strips cut 2" high (slightly fold to get in/out) and just 1/2" short of the length of the container the best.
Also as you will be buying them frequently (2-3 weeks) that should give you a endless amount of moths too.
The waxmoths are considered to be a treat though as they are so high in fat content, but if you are mixing in Dubias too then all your girl's needs will be met. Your girl though wouldn't complain about a diet of only waxmoths, mantids love them, but for nutritional needs the Dubia's would fill in the gaps.