although I’m sure it’s not what you want to hear tire temps are almost useless when it comes to tuning a kart. As you’ve already found, when a track is almost all one direction (like all tracks are) your temps simply won’t be even. You could try add a ridiculous amount of weight to the lefts to help them heat up more but you’ll go slower because the balance will be off. So what’s the point….
My advice on tire temps is that is can be useful when comparing front to rear temps to determine balance. Also check 3 spots across the front tires to help with camber. Then again, if a bunch of negative camber is really fast even though it wears out the inside prematurely, then is it wrong?