A Browning A5, .22 pump and another semi-auto shotgun along with your Parker. Enjoy
You are living right. As for firing the Parker, carefully study the barrels for any dents, bulges (however slight) or other signs of stress. If they appear sound they probably are. You have stated that it locks up tight. I would be comfortable with game loads and #7 or #8 shot. Remember, the wood on this gun is nearly 100 years old. Heavier loads are more likely to harm the wood then anything else.
Oh, looks like one of your other shotguns has a Cutts Compensator on the end of the barrel. The tube on the end is threaded and can be changed to other chokes. The tubes are hard to find, but are still around.