1550, I understand, and commend you for your digging up and figuring out what was needed to get the job done and obtain your desired results. Personally, I have a M/T drum brake rear, and have never had a problem adjusting them or with any pulling of one side over the other, but that is neither here nor there. I don't have a parking brake either, LOL
Anyway, part of the deal with Lehman brakes and conversions, etc. is the fact that Lehman is one of the only trike conversion kit manufacturers whose conversions are "DOT Compliant" To build and sell a conversion "kit" from drum to disk would have required Lehman to go back to the test track, instrumenting the trike, and performing all of the skid pad and stress tests for that particular conversion kit over again, making any corrections, adjustments, etc., so that the Dot Compliance standards could be maintained for that particular model conversion. It's all about product liability, something I, as a manufacturer of products, am very familiar with.
The bottom line here is that you were able to accomplish what you wanted.
Take care,
UB