Upgrade info

i recently got myself my ROG ally with the Z1 Extreme
I wants to upgrade my console to the mas but i have a question
Why doesn't Jsaux offer a bigger battery of 75wh instead of 65wh and also, is there a place where i can get the heatsink seperately so i can add the battery myself with the heatsink?

i want to get more battery power and have better cooling

does anyone have any info on the heatsink or maybe a 3d model that i can source it from somewhere?