Re: Hello from Clayton Delaware
motomanic- I haven't used one of those, but I've heard good things here about them.
If you're feeling industrious, you should be able to make one up yourself. I think CMB even had a 'how to' on their website at one time.
Bridging the seat and chain stay is probably the best method if you choose to use a tensioner. It has it's benefits, like ease of installation.
Chain alignment is the most critical issue. Straight as an arrow is the only way.
It's cooler to not fall off your bike.