I'm glad we could help. The binder/bulldog clips can be found at office supply stores or places like Walmart. You would want the largest size (about 2" wide). Luggage straps can be found in the luggage section of walmart or similar places. I'd get them sooner rather than later..Baby snakes are very thin and can squeeze through tiny cracks.
I forgot to mention that soldering holes into the tub in a few places will help with ventilation as well. I use a soldering iron for this and some people use a drill bit.
My boas enjoy climbing even as adults, which is why I went with AP's basking shelf option and also put thick branches in their enclosures. My adult male BCA is often out on his shelf or laying on his branch above the ground.
Make sure the AP cage you have selected is taller than 12". The 12" tall ones can be hard to reach into the back corners for cleaning.