A big target at 25 yards is how I sight in. I’ve tried boresighting, although not with a laser, and I’ve not seen the success that others claim. Ends up costing me more ammo than I want.
Now I boresight at 25 yards, put one hole on the target, then measure and adjust. Roughly 0.75-1.0” low at 25 yds is pretty close to a 100-yd zero for most centerfire cartridges.
Just my thoughts on it, not saying you can’t effectively go the route you’re thinking.