[waster]

Maybe too soon for me to be answering, but I'm running two now, though one is not-for-profit. The for-profit one I founded in part to generate a percentage of profit to seed the not-for-profit.

I say too soon because I haven't released the for-profit one to the world yet (still coding). The nonprofit has generated substantial interest in its field, despite minimal funding to date, and netted me one full-time job offer at the pinnacle of the field, and likely played a role in some other contracts I've had since.

But I don't know that two at once is right for most people. It's pretty insane, and probably only works for now because the nonprofit is in partial operation (advocacy) and the for-profit is in development. But then both are seriously big-scale in terms of their aims, so maybe that doesn't help, given that you said both of yours are small.