Heya Dunc
What have you done about an ATO on this tank ?
Besides that dead horse;
One thing you could try would be to put a 'tee' with a gate valve on the return pump, and have it dump back into the sump.
I had to do this with my current setup as the plumbing doesn't allow for my pump to run full-out.
Instead of tuning my drain, I tune my return. It's been flawless for 2-1/2 years and my pump isn't strained with any restrictions.
The only time I have to fiddle with it is when either the pump intake strainer gets mucked up, or if I've had my arms in the water for awhile and the displacement messes with things.
Maybe one day I'll bump up my drain plumbing from 1" to 1-1/2" ...
