Shooting the 1377 in pistol form

I'm no way a pistol guy because my arms are heavy clubs and I shake like crazy but I thought I'd ask if you guys have any tips on shooting a 1377 pistol without depending on a stable base to lean on...

I'm trying to shoot dime size targets at 10 yards...

I notice that if I have a light calm hold (middle finger and thumb), the muzzle rises during the shot... When I have a firm grip, I can't keep my aim steady...

I kind of have a way to shoot mine by using the weight of my left arm to counter the muzzle rise and pulling the trigger with my right hand.. And I'm getting 50 cent piece (remember those?) groupings but I thought I'd ask you pros if there was a better technique on how to handle the gun to shrink the groupings...

Thanks...

I hear a "Practice!" coming on and I will do that... LOL