I do think itd be easier to get a one set time for everyone to get on and do it on second thought. I can go several hours to a day when i just cant really get on.
We tried last year and we had nearly 1/3 of the league who couldn't make it to the time we wound up going with.
I missed both live drafts the last two years and I know we've had probably ~50% participation at said live drafts. In theory it shouldn't be that tough but in practice it has been. Doing it on the board guarantees everyone gets a player they actually want to draft instead of running out of timer and getting a default pick or worse missing the draft completely. It provides much more time for research for each pick compared to 90 seconds. I think it is great.
You don't need to be on every second of the day, we are all active enough around here that just checking it as you get on should be fine.. any luck at all and the draft will be fun for everyone and you will want to check it as much as possible, but hey, I'm not holding my breath.
We have well over a month to get er done, if things are going poorly we can audible and do a live draft if worst comes to worst. We have nothing to lose by giving it a shot.