Simple question, if you did 8 GLs with one class in a day, should you end up with enough SP to reach the next rank (assuming you were starting with 0 or almost 0 over the min for your current rank)?
If you say yes, then it'd take 50-100 days just doing GLs to level one class (depending if you can only do them one every one or two days). So you could level one DoW/DoM and one DoH every day.
If you say no, is that because such rate of gain is too fast or because it is too slow?