I just stumbled on your question. Relative position CG should not change with %-ual resize. It stay's above pointed section in plans. So scales with size.
You did a very nice build! Tunred it into a nice AMA Patternflier! Lowered the wing a bit :-)

I have a standard size to restore/fix. Planning to narrow the tail section, for better airflow, so the lower part of the rudders becomes functional. So, more tapering, like 'normal' planes...
The wide-bodied rear section works as a 'Kamm-tail', and the airflow never touches the lower part? Makes the ruther therefore less efficient?
Model designer intended it to look some what look like a Jet-trainer?
I remember there was a glitch in the design, and makes it uncontrolable in some cases, causing crash at low altitude, and to litlle time to restore flight.
Hadn't Art Schoeders Eyeball such an issue too? And was the tail lengthened by Eureka Aircraft?

But lowering the wing causes less turbulence at the tail plane? Finish it, and fly it to perfection and fun. Very cool plane!
Cheers RCP