i just started playing more tables and have been tiling 6 with some overlap and then stacking 2 or 3 on one spot.
if you're playing on more than one site you need to make sure each stack only has one site in it though, to avoid calling off 30bbs with 94o
also if you get deep it's a good idea to have that table on its own.
interested to hear people who are better at multitabling that me's opinions though, seeing as i only just started playing >6tables and i'd like to hear how they do it.