A good way to keep an eye on the oil system is to put some marks on the oil reservoir, I'd say at pint (16 oz.) increments. Then, at 40:1 ratio, you should see it go down a pint every five gallons of gas. You could empty the tank and then add a pint at a time until it's full, but then you'll have to bleed the oil line. What I did was just to run it as low as I was comfortable with (even running it low gives you a chance of getting an air bubble), then add a pint at a time and draw a line to mark the level. Would be nice if they'd done that from the factory... Then, line up the mark on the pump with the arm; you can find plenty of instructions and pictures with a search. If it's way off (especially to the lean side), you may have a problem to fix. They tend to be a little rich from the factory, so if you're at, say, 30:1, adjust the pump down little by little.
Once you've got it dialed in, make sure you're refilling the oil at a 40:1 ratio (some guys go slightly more lean) every time you add gas. If you see a sudden drop in oil use, investigate and replace the oil pump if there's any question. A sudden, complete pump failure could still catch you, but at least by monitoring it you have a fighting chance of catching it. That said, I'm around 4500 miles on the original pump. Usually the oiling burn-downs on these are from losing the pump drive (800s like yours can break the oil/water pump belt; ones like mine are driven off the crank and can strip the gear, though that's less common), so I wouldn't lose sleep over it once you've replaced the belt.
As for pre-mixing, some guys still do that. If it does any good, I'd say it's from adding some lubrication you don't get from the injection more than preventing a burn-down as a result of a pump failure. My thinking there is that if you add enough to go 10-20 miles without damaging the motor, you're going to be stuck running a lot more oil through the motor than necessary. Even at 100:1 pre-mix (a pint to every 12.5 gallons), you'd take a 40:1 mix from the pump to 29:1 total, and even 100:1 probably isn't enough to get far if the pump dies.