Correct, the samples in the video are 3d printed. Those are PLA (not safe to print ABS in my dorm
)
The final parts are being injected molded and will be ABS. So the finish will be far superior.
ABS is what was used on an older version of the system on team 811's robot last year. It worked very well. The right amount of flex for the clips. Plenty sturdy.
I don't have a scale to measure my parts but this is what I base my estimations off of.
There are ~330 meters in a 1 kg spool of 3d printing plastic.
Printing a cell takes me 8.5 meters with support
Printing a cell takes me 10 meters to print with support
A final cell should be less than 0.03 kg or 0.066lbs.
A final mount should be less than .045 kg or 0.1lbs.
This is calculated with PLA, which is slightly denser than ABS.
I hope that answers the weight question.
I did an early poll with about 30 teams. The majority of teams preferred the larger bolt which was also easier to use with a peg board. The way the lip system works we only had to bolt down every other cell last year, which was actually close to overkill.
My opinion on it was that if teams are diligent about weight at the beginning with a similar concern level to yours, then they will unlikely have a problem with the weight of 15 1/4x20 nuts and bolts.