Nice job - it was a good solution to his needs. Can't believe the sump dropped like that. I've actually seen a big one look like that - it was a guy moving from California to Texas, and the trailer came off the hitch and the ball slammed through the sump's end wall. I ended up routing off the end and gluing a new piece to the four walls. He picked it up and I never heard from him again. He was supposed to do some welding for me, now that I think about it. Grrrrr.
Ouch...glad you got it sorted, but man that's some bad luck...end result looks real nice though