I see what you mean Gypsy R. Good point.....mystery tranny tube appears same exact length as 'stock tube'. You never know though the measuring tape is hard to guage down there. I'll be swapping in that Ford Performance Tube eventually. But I'm with you, by approximation in here....short of foamy will work!
I did more research on this and the lengths of the sticks n' tubes seem to be all over the place. One guy wrote:
"I had a trans guy tell me that on a C-4/5: Start you truck, pull out the vacuum modulator and fill untill fluid comes out of the hole where the VM was. Reinstall VM and mark dipstick as full COLD..."
Only problem I'd say is it goes against checking your level with the thermal expansion factor when hot but at least it's a baseline for the next drain/fill.