I thought long and hard about the best set up for my rig, and spent a lot of time on this forum considering different options.
Ultimately, I decided to go for a 2 tier with the middle tier sunk. I wanted a stand that was relatively low to the ground so that I did not have to lift liquid above my shoulders when pouring my liquor into the HLT, and I wanted to be able to easily see into all vessels, especially the MLT. Additionally, I like the simple elegance of letting gravity do its work rather than relying entirely on pumps, so a 2 tier suited my needs (with one pump I can accomplish all that 2 pump single tiers can). Because I do not direct fire my MLT, but do I use burners for my HLT and BK, it made the most sense to gravity feed my MLT. In theory you could use this set-up with a direct-fired MLT though. Having my MLT as the low point also gives the added bonuses of making it the easiest vessel to work with (i.e. for stirring) and allows it to benefit from the heat of a burner on each side. Ive brewed a handful of batches using this Bad Larry and haven't looked back.
Full plans and more photos
here.