In the spirit of DIY, here is the manometer I constructed with a temp gas tank attached (see attached picture). It was more expensive to construct that I had expected.
4 gauges (Canadian tire - $30/each)
2x4 x 6' (old stock)
Square metal base (found in ravine behind my house)
100 lb Castor wheels w/brakes x 4 (Home Depot - $5 each)
1/2 x 20" Copper pipe (old stock)
Rubber caps x 2 (Canadian Tire - $2)
Air hoses and air valves (aquarium store - $4 + $1 each)
Brass fuel couplers -splitter, 2 barbs, valve (Canadian tire - $30)
Fuel line 2 1/2' (Canadian Tire ($10)
Washers and bolts (old stock)
Tank - cookie tin, seams filled with solder (old stock)
Paint - Black and Silver (Canadian Tire - $7)
It was a toss up between using the old cookie tin and an old turpentine can. Can didn't need sealing, but cookie tin had wider opening for filling with gasoline.