The one account for all thing is often mentioned as a 'selling point', and as of now I think it's rather ill-advised, setting up disappointment & possibly obershadowing a couple of nice things in that regard. A rather smooth part of the fediverse is that for example comments you read may stem from a lot of different corners, and writing one of those should work fine.

Regarding number of accounts you could experiment with a min or max approach first and then adapt based on your needs and experiences. You could re-use the first half of your handle, as the comment about identity suggested.