I think your right that if you have some up trim it will influence your knife edge. This is very true. Been my experience that changing CG has little to no effect on elevator trim setting and certainly I have never been able to eliminate all my up trim with just a CG adjustment. All it did was make inverted flight more hands off but knife edge still had a pull due to the up trim in the plane. It's my belief that you must get your CG as close to the design CG that you can pre-flight . Test fly your plane with trims neutralized and make wing panel adjustments to establish straight and level flight. Then you can revisit your CG position for optimal performance. This is a very subjective subject. If there is 30 responses there will be 30 different opinions most of which will hold true for one reason or another.
The Integral is a pretty solid proven platform to start out with. I'm pretty sure he is only going to need a positive wing incidence adjustment to fix his problems then a CG adjustment to fix knife edge flight. Like I said make a flight with neutral trims and note how bad it wants to dive. Land the plane and and adjust the wing. Make another test flight and I bet you will be amazed at the difference. Keep adjusting it till it flies straight and level. After you dial it in check your thrust line with vertical power on climb tests and straight and level flight tests. Start out at mid throttle and then ease throttle to full and note any dive or climb and adjust thrust accordingly. It will take many flights and lots of very calm air to get it right.