I was unable to hold the plane hovering more than a few seconds because it was very unstable and started immediately torque rolling. With a lot of effort I could resist up to two or three torque rolls before the plane drops.
After I modified the rudder making it taller and move the c.g. back a bit ,the plane performs very differently. Now it's very easy to hover but it does not torque roll at all. I can hold a hover for as long as i want to with no effort.
Maybe some of the experts in this forum could explain this torque roll effect.

Idid the same thing on my katana. it hovers with little efoort and torque rolls almost by itself once it let it.
maybe you made the rudder too big...
what plane is this?

try helping it to TR, some planes need the initial turn to be made by the pilot, left ail. input, and then they pick up throm there.