The Tango, Sticks and Knife Edge.

High wing plane, even those without dihedral will roll in the direction of rudder. In knife edge, they will roll out. Most of them will also have pitch coupling and will pitch toward the top of the plane. If you aren't expecting this and aren't very experienced, the plane can be all over the place.

I don't have a Tango yet since they are on backorder, but I do have a few Sticks, including an Ultra Stick 40 that will do knife edge loops Since the Tango has a good bit of side area, I would imagine it will knife edge nicely and probably knife edge loop.

Roll coupling: A high wing location is the equivalent of about 3 degrees of dihedral on each side. It will cause roll with rudder. Sweep back will also cause roll with rudder as will real dihedral.

A low wing location, sweep forward and anhedral will cause roll opposite to the rudder. Build a low wing plane without dihedral or sweep and you'll see what I mean. Right rudder will give a left roll.

All this means that a high wing plane needs anhedral or something to cause an anhedral effect to kill the roll. On a wing that comes in 2 pieces with a dihedral brace, you can modify the dihedral brace for 3 degrees of anhedral as I do on my Sticks. See photos. On a 1-piece, flat wing plane, you'll need to add downward end plates. See photo. I would guess that 3/4" down would be about right. My test Little Stick needed that much.

For pitch coupling, you can try moving the CG rearward, but the best thing to do is to mix elevator with rudder. That's what I did on the UStick. It now does the knife edge loop with very little effort. I am using a 52 in-oz digital servo on rudder.

As for the one powered by a Magnum .70, I have that engine and it is 5 ounces heavier than a .46AX and 4 ounces heavier than an OS .55AX, plus it mounts slightly further forward due to the rear carb. This will tend to make the plane nose heavy. Add a heavy battery pack up forward and I am not surprised that the snaps are spirals. The plane must be really nose heavy. You might need to move the battery back into the rear fuselage, behind the wing.