I say, go all in.
15 days. 30 rounds. Or, if people are up for picking at night, do it in 10 days (two rounds during the day, one in the evening).
Mandatory positions:
Offense (11): QB, 1 RB, 3 WR, 5 OL, 1 TE
Defense (11): 2 CB, 2 S, 3 DL, 3 LB, 1 DL/LB
ST (3): K, P, KR
Coach (1)
Wild cards: 4 total, minimum of 1 each on offense and defense
Yes, participation might lag for some. I say, who cares? Keep this less competitive than the CB draft; if people miss picks, the Commish can pick for them that night.