The displays are common anode, and crave 8-10 V at a max of 25 mA. Using the 74LS192 to sink 16 mA *should* give a bright enough display. After a quick test setup, 9.4 V at 15.2 mA is a little on the dim side, but it would suffice. I'm going to at least 20 mA though, which is very easily...