Hello to all
Here's the original post on this project and a summary of pic's that completed the job.
The only thing I changed was instead of starting at the high point, then moving around the perimeter to make it level, I raised the high side by 1.75" so I wouldn't be pouring real thin. This did raise the low side up to 5.5" bc there was a 4" delta over a 48" run; so an inch every foot.
ON the 4th pic w the level, if you view the inside beam of the new pour on the left, you can see as it moves forward, the pour raises up to 5.5". that root really raised the S side of the slab.
I acid washed the pour area, then used a sticky glue as advised. The wellhouse is very level (and raised) now.
Thanks to all for your help,