If you're pretty serious about being done in the near future, and are intent on keeping the machine until then, I wouldn't mess with the fuel screw, especially since you've just had a head gasket failure. Could be a quick way to fail another. Lots of good suggestions, as someone else mentioned, I would probably shoot for the least expensive of the upgrades, and I'll give you a recommendation that's just about free.. nothing saps power like uneven feeding, if your 1020 is anything like my last one was, you'll go 5 or 10 feet without taking hardly anything in and then take in a bunch at once, rinse and repeat. Forces you to slow your ground travel. There's two fixes for that that I know work (grain grabbers ain't one of em, was a waste for me), you can buy a draper, or you can cut at an angle which will even out your feeding. I could easily pick up 1 to 1.5 mph of ground speed on an angle as opposed to cutting with the rows. To me it's the best bang for the buck you can get, unless you're already doing that and still crawling along.