My buddy is 5"10 and he does ok on my single tier. 32" tall + keggles. i'm 6' and it's a bit of a pain to stir the MLT but we bust out the step ladder for him. I have the pumps and plate chiller under the MLT to keep them away from the heat of the HLT and BK burners. Propane tank is 5' away from the stand for heat, warming, and easy swap out reasons (we do 4 batches per session).
I have the casters not on the "bottom" but on one of the ends. When not in brewing use most of the gear (including 3 keggles) go on the inside the stand for storage (the main reason it's so big/tall).