I would load for however you intend to use it the most. Meaning if it will mainly be suppressed, develop your load with the can attached.

I have found in my defensive ARs that the accuracy and "combat effective hits" out to 200 yards does not change enough to warrant different loads for loud or quiet. My long range precision rifles really only get shot quiet so I developed the load for those with the can attached.

In terms of your 300blk, I have a 7.5 inch that rides with me. Suppressed and loud with supers does have a couple inch shift at 60 yards. For a little truck or camping gun I feel that is acceptable. The biggest difference I found is when going from my zero with supers loud to shooting 220 grain sub suppressed. I have to spin in a bunch of windage adjustment, roughly 10 moa worth.