The biggest will need to be 75cms high some 55-60cms deep, 120-130cms wide, open at least front to back (it'll straddle a 40d x 90w drain) and with no possibility of a central support except at the very front. It'll be for two 250L butts, so 500+Kg.
Happy to hear ideas. Cost is a consideration.
(A little stuck on thinking about timber based stands as I can't seem to find a load bearing calculator anywhere that will tell me if, e.g. 2x4s on edge will do it or if I'd need to get bigger and/or double up and/or ... so if anyone knows where there's one, please link!
![Wink ;)](./images/smilies/icon_e_wink.gif)