you can get little half round clips that screw or glue to the viv then u just clip the tube in to these most pet/reptile shops sell them and there only a couple of quid
Using it for a kingsnake, viv is quite high though, does the surface get hot on them, i am only using the 20 watt one so it shouldnt get that hot surely?
if your overly worried about it you can always make one out of mesh or the like just dont put anything solid in front of it as this blocks all the uv
no they dont get overly hot