I had the 1/2A6-0 on my list as the last item.
I'd like to also add in the following:

ANY 18mm BP D engines of any length

A REASONABLY priced (street price no more than 25% above the street price of an Estes SU D) 18mm composite D that actually makes it to production and is NOT vaporware like the Enerjet D21 or Quest "coming soon for 3 freakin years" D.
Some reasonably (under $8/E, under $10/F) priced SU BP or APCP 40n-sec E's and 70-80 n-sec F's.

Some 13mm B SU BP engines like the old Centuri B4-xM

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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 !