A few hours is a bit much IMO especially if you will have the majority of rock out. I wouldn't leave rock out of the water more than 30-minutes and even that is pushing it (again, IMO/IME). Don't overthink this. Mix up some new SW for a WC and fill your bin(s) with the old water you drain out of the display to keep your rocks wet as you rearrange. It will be good to do a WC in conjunction with all of this anyway. You will be surprised to see how much detritus is on your sandbed under base rocks of your current pile and you will want to siphon that out. I personnaly despise using the exopy putty but it will set set enough that the rock will "stick" (but not completely hold if you bump it around) fairly quick. I find that rock will typically fit together one way or another and even breaking a rock here or there will give you the pieces you need. Grab a few beers and pop a few chill pills and you'll be good to go
. Good luck!
I dont think I will need to have any single piece of rock out of water for more than 20-30 minutes anyways so that works out in my favor. I can just take a rock out, see how it fits with another rock, apply some putty if need be, and then throw it back into my display.
I was specifically thinking about all the detritus underneath my rock as well, that's actually the main reason I mixed up a 20 gal batch of SW...The one problem I am seeing is that I will probably need to make more SW because I am going to be taking out 20 gals of tank water to put into the bins for my LR. But since there is so much sand bed that needs to be siphoned(honestly I haven't really done any siphoning in about a year since the tank started running), I will probably be siphoning out another 15-20 gallons of tank water while I am siphoning my sand bed...so I forsee myself going to home depot to pick up another can to store water lol.
Whew, some elaborate planning going on here lol. Will definitely need to grab a case and set up some music while I do all this lol