My propane locker and tank are listed under Seward part number 93268. The locker fits within the lazarette locker with an inch to spare in height.
The tank capacity is one-gallon.
The photo reveals that I tee off a second line with a second bulkhead fitting (upper left) that extends to the gas grille on the stern rail. Both interior stove and external gas grille must be connected and gas-tight before the solenoid (green, at upper right) is ever turned on.
I converted my Force10 gas grille to a low pressure gas valve (which implies higher flow rate for a given heat setting). Because of that, it can be problematic if stove and grille are both on and calling for a significant gas flow...the propane regulator can't handle it and they will starve each other. If this was really an issue, I'd use a high-pressure gas valve on the grille and plumb it into the high side (before the regulator in the locker.)
I more recently installed a guick-disconnect fitting at the outside grille to make it easy to remove in the winter.
The locker is vented at the bottom, which required a matching hole in the bottom of the lazarette locker. A brass hose barb was screwed upward into that threaded hole. A hose is routed between the brass barb and a thru-hull near the lowest part of the transom.
There is nothing special to venting the locker...just a hose barb and a thru hull. The whole vent scheme needs to be kept lower than the locker. It turns out that there is enough room below the lazarette locker (accessed thru the inspection plate in the bottom of the lazarette) to install and route the hose and fittings.
The tank weighs 12 pounds empty and 16 pounds full so I carry a scale to check it periodically. As a spare propane supply, I carry several one-pound Coleman propane canisters (with a brass threaded cap as an added precaution against leakage.) This adapter connects a Coleman propane canister to the standard tank fitting used in the locker.
The Seward stove makes efficient use of propane. Our propane usage averages between one and two tank fulls each summer.