If that is the Lamont society you are joining, then I would say that is the best option. If you are a Texan, then the Bluebonnet would be a close second. As for the weight of the tartan, that would depend upon its availability in the mill and color scheme you prefer. I would go with the 16oz if its available in the tartan you choose. I doubt you would see much difference in the heat factor between 13oz and 16oz in a full 8yd kilt.

If you are looking for a different universal tartan, I like the Hunting Stewart in ancient colors. It has military traditions as well as being universal.

This is a large investment. I would get swatches in the different tartans. Even swatches of the same tartan from different mills and choose the one you like best.