I wouldn't run shims , you chance running the converter too far in its hub & it could damage it, plus you won't have the support of the whole circumference, just little round washers & risk too much flexing which could crack the flexplate, now if you used a shim "ring" to go around the whole area that might work, but you still risk what i said earlier in this post. I'm shure the ring gear is in the right location, you can run a straight edge across the bolt pads & measure the distance down to the top of the ring gear & varify it with PTC, If its good, Then i would just spend the 60.00 & have it done, But i would call PTC & see what they say, something ain't koshure.

Did you get the 7/16" bolt holes, I never get an aftermarket mopar converter with the stock chinsy bolt holes anymore, they tend to come loose, the 7/16" most likely never will.