As space is tight, don't build a mock-up tank that is flexible, even thin wood will move too much. Ask me how I know...
If your existing stands are steel or correctly build wood, is very simple to move them around with a hydraulic car jack and several small platform trolleys. Invest in low height ones so you don't need to jack up much or build own. You still need to drain almost all the water to move the tank but substrate and fish can remain.
If all else fails, it's quite easy to add an extension onto a tank so you can lengthen or widen or go around a corner or even surround a fish room structural post on any tank provided you don't mind a visible seam. This is no different from having a corner seam if you think about it. I've joined 3 and 4 tanks together and there isn't a limit.
If your existing stands are steel or correctly build wood, is very simple to move them around with a hydraulic car jack and several small platform trolleys. Invest in low height ones so you don't need to jack up much or build own. You still need to drain almost all the water to move the tank but substrate and fish can remain.
If all else fails, it's quite easy to add an extension onto a tank so you can lengthen or widen or go around a corner or even surround a fish room structural post on any tank provided you don't mind a visible seam. This is no different from having a corner seam if you think about it. I've joined 3 and 4 tanks together and there isn't a limit.