Depending on the chassis, most older ones like a left rear to be 5-8 points harder than the rights, and most newer chassis like the left rear the same duro as the rights or just a couple points harder. I run mine the same as the rights on a 2012 shatter racing chassis. Using what you have, use the softer set when the track has moisture, and the harder set once the track dries out or is dusty, go up on air according to track conditions or as the track gets harder and picks up as the night goes on. Both sets you have should be right in the ballpark for springtime racing, but you need one more set that duro 56-58, you can just pick up 2 right sides and a left rear, and use the left front from your set that punches 52. thats what i do, i use 2 left fronts with all my sets, one is around 50 and the other is about 58. I match my sets as RR, RF, LR. Work your tires thru the week with a conditioner and build bite into the tires. Track Tac Black Sand is a good prep to use thru the week when you know you will be racing on a dusty track, it adds great bite and conditions the tires also. I use it alot thru the summer, and use alot of Venom Bite Blue in the spring, with good luck.
