The problem with the manual tensioner is not the tensioner itself, it is the corresponding belt due to dimeter diffs. The AEB used two differnt belts. The early with used a horrid tensioner setup that was prone to failure and used a (152T belt). The Revised hydro tensioner similar to later 20vs used a 153T. The IE setup accounts for this belt length difference for the Later 20vs and uses that extra roller bracket.
You can use the 16v manual Tensioner on the 058 block and AEB head. You will need to flip the roller and use a Shim behind it along with the proper Stud due to mounting depth diffs on the head. I am not certain on what tooth belt you would need for this setup, but my guess is that either the 152 or 153T would work. YOU NEED to VERITY THIS though
Another option is using the later AWP Roller, removing teh hydro tensioner bracket and placing a washer between the bolt and roller to make the tensioner fixed when you tighten. THis Roller has a slightly larger diameter than the 9a though and would most definitely require the 153T an would hopefully be long enough. My gut says yes, but you need to verify.
I used both setups on the AEB and other 20v heads for various reasons. All were on the ABA tall block, which is why I disclaim knowing the exact belt lengths. I seem to recall though that 153t was perfect for 20v on G60 Block (same deck height as AEB) using the 9a roller.
Finally, the 9a is MUCH cheaper than the AWP route, but just so you can see what I mean, here is how you would make the AWP work. <- can't seem to find my pic of the AWP...
Going to need to use a modified serp crank pulley too as the AEB will not work (5 rib. etc)
Lots of info that is directly relevant in the G60 20v thread in the G60 Forum