i use a simple primitive model with a single color/material to it then scale it based on the distance between the 2 points needed

( so you need a little math in there for your scaling... model is Z quants long and then distance points A<->B)

distance / modelZ ( min result of 1) = scale

the 'bottem' of my model would be centered and flush with its origin so model starts at point A align model to direction of A<->B (direction vector) then scale it ( above)