Call whoever is building the driveshaft, they will let you know what measurements they need. I just had one built and it was from the trans seal to the yoke flat.
or
https://www.summitracing.com/parts/trd-1122?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-trans-dapt-performance-products&gclid=CI2v-N2W3NQCFdG1wAodNzAHlg