My sporters aren't all bolt actions, some don't have free-floated barrels, some are pretty light too. The technique I use tends to be the same though, either zeroing or testing loads, and that is to hold the rifle in both hands, just as I would if shooting in the field, with my weak hand holding the fore end and the back of that hand on the front rest.
FWIW I've found that letting the fore end simply rest on the front rest, and even more so letting the rifle free-recoil, affects POI as compared to holding it, especially with light rifles. This should not be a surprise of course, given that a rifle starts to recoil before the bullet leaves the muzzle.
I pay particular attention to maintaining the buttplate on the same position, and fairly firmly against my shoulder (but not so firmly as to cause muscle tremor). I also pay attention to such other things as keeping my elbows in the same place, my trigger finger clear of the stock, my forward hand in the same position, and my cheek in the same position. I also watch to make sure that swivels etc aren't snagging.
FWIW I'm just as happy shooting from lying supported, using a sandbag or a daypack, as from a bench.
I do much the same. I am a decent shot, but no expert, and I admit I've had some issues with some rifles from the bench. The conventional bench rest wisdom was to grip the rifle as lightly as possible (free recoil). For me and light rifles, this produced poor groups and no control. It was also not very comfortable. I then figured that this advice was best suited to rifles with light recoil or muzzle brakes. As as example, having one hand on the pistol grip and one hand at the back of the stock works fine on a typical AR rifle. But not on my 8 pound 30-06 sporter.
On those rifles, I got better groups from a firm grip on the fore end with my non trigger hand, and held the rifle firmly in my shoulder. Firm, but not excessive force, as appropriate to the recoil of the rifle.
With these steps I got reasonable accuracy groups. Some serious shooters advocate shooting from the bench with barely any grip on the rifle except to pull the trigger. I can not understand how this would work, at least on my light to average weight rifles. They probably have 12 pound plus rifles and muzzle brakes. When i tried this I had no control over the rifle and it jumped all over the place.
But that's just me. Bench shooting does seem to make the recoil feel much stronger compared to offhand shooting. From my offhand practice, I am accustomed to keeping a solid grip on the rifle, so I am comfortable shooting that way. And a light cartridge like a 223 in an AR is way different than a medium weight bolt action shooting a 30-06 type cartridge.