I did not end up using the tensioner, 'cause I got lucky with my vertical drop out install and was able to get the chain length right.
The spacer kit and gear worked well, but I had to use a thin spacer, not provided, to get the overall chain line straight. I can't blame the kit though, my bike is a 7 speed, not the 8/9 speed advertised.
FIY: the application was a 90's era Stumpjumper with a chrome-moly frame.
works just like it should, keeps good tension on the chain. chain hasn't popped off yet, even with all trail and DJ riding. makes it super easy to convert to single speed with the kit. I recomed this product to anyone looking to go single speed.