I have the V3 OMP Edge 540 and when I cut the throttle the plane climbs a little and also when I try landing it wants to float forever and I actually have to feed in down elevator to descend. Do I need to add up or down thrust to solve this?

Sounds tail heavy.
How does your plane fly inverted?
I have 2 degrees right thrust but nothing up or down. For 3d profile the jury is out if any right thrust is needed. It is a little bit of personal preference.

You are the 3rd person to say it sounds tail heavy so Im going that route, I added an ounce of weight to the nose so Ill fly and see how it goes.

If you cut the throttle and it climbs you need more up thrust because of the trim on the elevator during normal power on flight.

If you turn your plane inverted and it stays level and slightly desends then you need more tail weight or you can leave it alone most people will tell you to invert the plane on an 45 upline and if the nose doesn't dropall of a sudden you are good but i like my planes to be the neutral inverted.

Before you go tinkering with the up/down thrust, are you absolutely sure that both ailerons are adjusted to be perfectly parallel with the horizontal stab? If the aileron rigging is misadjusted, it will cause the elevator trim to be misadjusted, which could cause the problem you're describing.

The OMP Edge V3 is an excellent flying plane when setup 0-0-0. I've never seen one yet that needed any thrustline adjustments other than some prefer a small amount of right thrust.