Two issues to deal with on any ultra light:
Barrel whip
Length of time the bullet is in the barrel
I have had the following model 7's:
222
223
243
7/08
308
All of them were typical in their groups. 1" was stellar and 1 1/2" more typical. I bedded, replaced stocks, free floated, became an expert of sorts on pressure points, and actually put adjustable pressure points on one forearm to try and help it.
What worked in spades was a putting a Gentry muzzle break on the barrel. This I think did two things, eliminated 50% or more of the recoil, and added weight to the end of the barrel. The gun is moving while the bullet is still in the barrel for about .200 of an inch, Reducing recoil helps tremendously in this regard.
I still have 4, the 243,(2) 7/08's, and the 308 all shoot with the bullets touching with Gentry Muzzle breaks, otherwise, they are shotguns with 2-3.5" groups.
What I have done since on a couple of other carry guns, is to install a #5 contour and cut it as short as I want, stiff barrels work in spades, but it does add about 1 lb to the weight MAX.
Bughole load development involves little work on the short stiff barrels.
I had a couple of ruger ultra lights, got rid of them at a gun show, this was before I learned about the muzzle break fix.
I had a gunsmith friend in San Diego that did nothing but build ultra lights. He came over to Az and hunted with me from time to time. He told me that ultra lights were never intended to shoot groups with, just to hunt with. He hunted coyotes with a 7 Dakota that weighed 4 1/2 lbs with the scope. I swear, it was the most brutal thing that I had ever pulled the trigger on.
If you do build a model 7 and want a tack driver, make the taper a straight taper from shank to muzzle dia that you want, and this small amount of additional steel will add great rigidity to the barrel. This "straight taper" is an old European trick to make barrels more accurate, nothing new at all.
Good luck