Swelling the seals to prevent a leak is a common patch. I'd say that it really doesn't fix anything, as you're still leaking oil.

Depending on the reason for the leak (old seals, a groove worn on the sealing surface etc) swelling of the seals may not do much.

Not sure if a 49 would have the rope seal or newer neoprene type. My 42 was rebuilt with rope seals but that can also affect the swelling action.

I would consider 1qt every 200 miles a serious enough leak to fix ASAP. Seals are like $20 and doing the front and rear seals on a 216 is something you can do without taking the motor out. Your driveway must look like a BP oil spill.