i went thru the 12RR to 12RRlipo to CH12 stages(i have a box of stuff that you can PM me about if you are interested) but taping the battery will be the same situation. instead of a locator, you can add friction between the battery and chassis so when taped it will slide less, and just tape it down a little more forward to avoid the battery fouling the flex plates.
as for a front brace, a 2 piece style like the serpent or others, lets you use orings to adjust the width. i looked at a 12rr chassis and the brace length would need to be about 46mm and the serpent can be 44mm to over 50mm.
Thank you for the info Tony, I will send a PM with regards to bits and bobs. As this is my 1st 12th and I have lots of spares think I will more or less keep it as a 12R for a while and as u suggested increase the friction on the lipo.
I have a front brace on the way also
So do u now run a CH12?