You could look at Alister's nitrogen burst systems. He's an advertiser here. Of course, that's expensive.
For hangers in tanks, look at the threads on minimal agitation schemes. Less agitation, less chance for surge marks.
You could also learn to develop multiple sheets in trays. A lot of people handle 10-12 sheets of 8x10 in trays, though 6 is the most I've managed.
juan