Doing the G-T as an X-Kit would be fine by me and I think most other BARs.
I don't know about being an 'expert' but most on this forum are certainly accomplished model builders.
Tell 'em to print the instructions off for the original K-21 from the Jim Z site or another.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !