You can tilt the bike to the right to avoid draining the oil. I did. Gotta be careful though and tie a support strap or two to keep it from toppling.
On another note, how many miles will a water pump go once coolant begins coming from the weep hole?
No thanks, I will drain the oil. It is easy , fast and safer.
As far as the water pump lasting , I would think it should last until enough of the the water to leaks out or it stops pumping and it overheats and the engine seizes. I dont mean to be a smart ass but you know it is shot and needs to be replaced.
To be honest I have no idea how it it may last. You may get oil mixed in with the water or vice verse neither of which would be good thing.
This one is my 3rd one, my first one was bad/defective at a very low mileage. Good thing my mechanik caught it or I would have be stranded very far from home
It is not a big deal to change, it took me 4 hours and I had to clean up a large oil puddle, and I cut the 'O' ring in half on the hard pipe hose that goes into the water pump so the coolant leaked out and made another mess.
It looks like my old pump maybe ok, just needs a new seal.