Downgrade from 6.2 PR to 6.1 RELEASE?

[Chris]

I felt I should ask this question before taking a drastic action. I  
built this new production system complete with jail (which I can  
recreate very quickly) and all was running perfectly under 6.2  
PRERELEASE. I was planning taking a chance and going production  
(against common wisdom of running 6.2 PRERELEASE in production).  
Yesterday I decided to cvsup and rebuild one more time and discovered  
a glaring problem on this AMD64 Tyan s4882. It can't reboot with the  
reboot command or shutdown -r about 75% of the time, it hangs between  
the uptime output and where it states Rebooting, then requires a  
manual reset to get going again. This tells me I have to fall back or  
will create a nightmare for production use. Presuming I can live with  
certain driver issues on 6.1 RELEASE P6, are there any serious  
dangers or unique procedures in going backward, to RELENG_6_1 from  
RELENG_6 that suggest it would be better to just start from scratch?  
I've not fallen back from CURRENT to a RELEASE, this will be my first  
time.