I'm amazed you got five resets in before the drive spun right up, but anyways...
Creating a boot floppy that waits for, say 15 seconds, before warm-resetting the Amiga is dead simple. I'm not really sure there's much benefit to doing that, other than to assure a non-attended boot. Depends if you really have a problem with waiting around a few seconds for the drive to spin up.
I don't think soft resets on each boot have an adverse effect. Plus, you get to see that lovely rainbow-tick screen on every boot! :-D
Regarding power, I ran a 68030 accelerator and HDD in my A1200 using an A500 PSU for about two and a half years with no problems.