So my Motobat battery craped out after three years and it's time for new battery. I've had amazing good service from the Yuasa and Genesis (which I think is made by Yuasa) brand 6v 4AH SLA batteries. I started looking at what it would take to fit one in my RT2 battery compartment. The Genesis battery that's in my 250A is at least 8 years old. My experience, as long as you ignore them, do nothing to maintain they seem to last forever and their fairly inexpensive, $13.
I did some measuring and it looked like there is just enough clearance between the battery compartment and fender to lower enough to fit. I removed one of the bottom supports and added one deeper and trimmed a little off the remaining existing one.
 
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I lowered it just enough for the difference in height of the two different batteries.
 

Done and I can still use a "standard" RT2 size battery if I choose to.
 

New battery in and all's good.
 

The foam rubber block that's glued to the underside of the seat pan lightly touches the top of the battery and covers the connectors.
 

Nice work, looks factory! 

Thats a neat set up!... I put in a review about the motobatt having wires turning down.. Would be nice to have a top option... I looked at emergency electric brake batteries.. but veered away because of modding the battery tray.. which I don't have a welding setup.. 
Someday... Mine will look as neat and tidy as yers!
Sneezles61