Van,
40 Macs is a nice number. Mine does good with the regular sized macs but when you get the macs on roids in there the numbers obviously go down and the ability to swim harder.
The dual overflows are a good idea. So many set ups I've seen lack in the overflow area. If your pumping in....gravity out takes a bigger dia. My set up that I use now is a bit tall but the overflow goes right over gunnel so no need to go out the scuppers or drill any holes. The one thing I still have to remember is I have no check valve in the supply hose, so if I shut the pump off I must yank my hose out or a few minute later tails be slappin the barrel
I am sure this is the case with most set ups. Makes a good start to the morning turn crappy until more livies are caught. Actually dead trolled works wonders too, sometimes easier. I haven't been able to fix the problem of a weak bait getting stuck to the overflow outlet and then the tank starts overflowing in the cockpit yet.