Your tune should not change that drastically from day-to-day, unless weather conditions are way different.

You might have something else going on if the tune was that bad from one day to the next. You might have an air leak somewhere, an issue with your clutch or bad fuel.

Air leaks are one of the most frustrating things in dealing with nitro vehicles. Can be hard to find. If my "tune" changes very much from one run to the next, I start searching for signs of an air leak before I make huge changes to the needle settings. Once you have it running well, you shouldn't need to touch the needles very much run to run or even day-to-day. Most common places for air leaks to develop are fuel lines, fuel tank lid seal, around the base of the carb and the engine backplate. Also check to make sure your head bolts are tight on the engine.

I've also been a part of a number of "tuning" issues that ended up being a clutch issue instead. Worked with a guy all day once trying to get an engine running right. Before we started, I asked him when the last time he re-built his clutch was. Told me it was brand new. Came to find out that the clutch itself was new, but he had put the old clutch bearings back in and they were over a gallon and a half old. Caused us fits. Replaced the clutchbell bearings, went through a quick tune up and it ran like a dream.

Last issue is fuel. I hope you don't store it in your garage? It is old? Nitro fuel is hygroscopic, which means it attracts and retains moisture from the air. If your fuel is old, or has been stored in your garage, it might be going bad and causing part of your issues. Also, never leave fuel in your tank after you run. Dump it out or run it out, just don't leave it in there. If you had old fuel left in the tank, that might explain why you had the issues you did the last time you fired it up. Could have taken on moisture or gummed up your fuel lines, causing erratic running.