Here's my take.
Been dabbling with LiPos on my son's R/C rock Crawler with good results, so decided to give this a try on our 24V16
Bought two 6000mAh/20C 6S Chinese brand LiPos from the LHS.
Plastic junction box from a supplier at work
XT60 parallel 'Y' connector epoxied into the box
This was my 1st time using XT60 connectors; I previously used Deans and bullet connectors on the R/C stuff.
I found XT60s were easy to solder, but there is not enough space to insert two 12 gauge wires for the parallel Y connection.
The two 12 gauge wires together were too fat, so I had to trim away some strands and generally stuff around to solder two 12 gauge wires per pole onto one XT60 connector.
I experimented with different foam layers to get the batteries to lie snug in the box, finally settled on some computer mouse pads.
A two hour play ride with extended periods of WOT yesterday dropped the LiPos from 25.2V hot of the charger to 23.8V. I'm quite happy so far, the weight savings are massive. I think I'll invest in a 3rd 6S to extend the ride time even more. Lots of space remaining in the battery tray.