Chuck, I got Astra Zeneca two weeks ago because that's all that was available to me at the time. For me it boiled down to a risk calculation between the 1:100,000 serious side-effect vs the odds of getting severe COVID in the 5-6 weeks before an RNA vaccine is available to me. I did some scratch pad calculations and that ended up with raw odds of roughly 1:2,000 based on the average number of daily cases in my area. The fact that I have a daughter about to restart school increases my odds but the fact that I work at home lowers them. Either way, it doesn't approach 1:100,000. So getting AZ won out. I've had no issue so far and since I'm 15 days out, I'm pretty sure I'm ok.
I'd say the J&J probably has the same side-effect odds (although so far, it seems the side effect odds are lower than AZ). So you fudge that type of calculation for yourself, being fully aware of the side effects. Since you don't want the RNA vaccine, you'd be comparing the odds vs. not getting vaccinated at all. I'd say that weighs towards getting it sooner rather than later.
Note that for my second dose I'm hoping to mix & match with an RNA vaccine since my odds would change once I have some immunity. Plus, I like the idea of getting improved immunity from the mix (but that's me - I would not expect others to make that type of decision). Approval for mixing and matching should be given out here before I'm up for my 2nd dose (Canada is on a 16 week gap between doses because of scarcity).