I use a seamstress/tailors tape measure (from a 3-pack at the dollar store) to measure the length of track needed.
The jig:



I use the pins to mark the length I need. Using the measuring tape anywhere near the track after I've started building it resulted in pieces being dragged all over the place.
It's made of foam-core display board. The masking tape is there to keep any excess glue from attacking the foam.
I've had good luck with this jig. I tried the "work against the side of a ruler" method, but I would end up bumping the ruler, scattering the track links all over the place. The other advantage is I can move the jig to the side as I work, so the work area is always in front of me, instead of working more and more to the side.
The time need depends of the length needed, the size of the individual links and how clean the indy links are. It can be anywhere from 20 to 30 minutes to build a track, to get the Tamiya extra thin glue down only takes a minute or three. I give the glue 10 minutes to "bite" and then drape it over the wheels. If I've put enough glue on the links ten minutes is fine.















