I agree. This guy has tunnel vision, totally focusing on the SPRING TENSIONER and nothing else. Bandaid fixes might last until you reach home, or 700 miles.
Why do you need so much tension on your SPRING TENSIONER?
Open your mind! Look at the big picture, not just the SPRING TENSIONER. You have been offered a lot of good advice. At least take them into consideration.
Here's my 2 cents: shorten your chain. I'm presuming you're smart enough to shorten the chain so tight, that when you install it, you have to make it crawl up the wheel sprocket COUNTER-CLOCKWISE to install the tight chain. Make a better McGuyver fix. Don't drill into your frame.
Keep it simple, stupid(KISS). Some builders don't even use tensionsers.
I USED to use a chain tensioner/grooved skateboard wheel. After so many subtle changes in sprocket/chain relationships, my tensioner is no longer necessary.
Here's another suggestion you might consider "off topic" from your SPRING TENSIONER issue:
Reposition your engine mounting(maybe higher) to get a better alignment with your wheel sprocket.
And don't get bent outa shape with our suggestions. We're not there to see your bike's problem in person.