David, Mainly visual but Imaging could be down the track. Obviously, when I am sitting looking through the eyepiece I am not also walking around on the tank.
I have only had the pier set up for a couple of weeks and have enjoyed it on the observing sessions so far. If radiated heat from the concrete proves a problem in summer I may just try things like hosing the surface to cool it or whatever.
Bottom line is that this was the best possible viewing site available to me so therefore it must be perfect.
You could try a temporary set up in your position to check for vibration issues. Even just on a Tripod. If you intend to cover the tank with an Obsrevatory, heating issues might not be a problem.
Kangaroos and Wallabies gather on the tank at night, but so far not when I am osbserving
Pease keep us informed as to how you progress. I would be interested to see how you go with just a temporary set. Do you know someone close that has a similar tank that you could have a try on? My tank has a central concrete pier supprting the top from within and the top is 100mm thick with Reo bar in it.
Good luck.
Michael