Hello Kyle,
I've used the Reptariums in the past for my Knights and think a 65 is large enough for a pair (male/female or two compatible females - larger obviously being better and I've seen info. suggesting a 300 gal. or so is the minimum for a pair). The only drawback to them is their poor ability to provide for a humid environment. I used mine, a 260, outdoors one summer and I think my Knights' really liked it. However, when I brought them in, I just couldn't keep the humidity up, even after wrapping the thing with a plastic drop-cloth, which makes viewing a chore! I found the zipper mechanism to be a pain after several months as it kept snagging on loose threads of mesh material. Any way my post is digressing from your question. If you're thinking live plants go with a small Ficus or corn plant. Provide climbing branches, either driftwood, cholla cactus branches, some of the resin stuff on the market, or something you know to be clean and free of contaminants. Knights need plenty of cover to feel secure and I like to use the artificial vines that are on the market, which can also add a splash of color if you get the one with the purple on the leaves (I forget the brand name). For heat use an incandescent spot lamp or ceramic heat emitter, the nylon mesh is "supposed" to be able to tolerate the heat from these. I used a 30" metal screen top to support my lamps on top of the mesh, so that I knew it wasn't touching and did not cause the top to sag down. Day temps. should be about 85 to 90f at the basking site, with the opportunity to get cooler lower or on the other side of the cage. Nightime shouldn't drop below 70 to 75f. Humidity is tricky. I try to maintain at least 50% but I'm sure higher, 75 to 80, is better. Frequent spraying with warm water will help with this. I'd ditch the sand and get one of the liners made for the Reptarium so you can use a soil mixture, especially if you have a female who will be looking for nesting sites (usually at the base of one your plants). Also, keeping a layer of the moss stuff available on the market slightly damp will help with humidity in the cage. I'm sure I'm missing something, but this is quite a long post so I'll quit now. Hopefully the other Knight owners will chime in and fill in my gaps. Good luck with your Knight!
Chuck H.