In my mind the weight should be limited even in open, it's limited in other shooting sports, you have weight limits even in F Class Open
I would say 22LBS for Open and 18LBS for Limited, why because a Stock AI is close to 18LBS.
We have speed limits, caliber limits, etc, a weight limit in my mind would be without the scope, the scope is irrelevant to the situation.
It's a defined set of rules so everyone understands. 22lBS for a practical rifle sport is not limiting.
Open has to have guidelines as much as anything, rules matter. You'll see more innovation with the rules in place than without.
Remember you want to grow and add to the sport, in these cases perceptions matter, having no limits ruins the perception for a lot of people who want things defined up front.