Steadman,

Your questions:

#1 Yes, your link is heading toward the nylon Ts I use but you must further select color, type of barb and size. Only the size is crucial. I use the 1/2" Ts.

#2 Yes, Skyshark 400 or something comparable for 30-40 lbs. My wife's pack is using no-name fiberglass tubing but she rarely carries more than about 20 lbs.

#3 Yes I have used the .240 ferrules. Either carbon fiber or fiberglass is fine. I haven't tried the .25od ferrules and probably wouldn't use them. The id of the Skyshark 400s is .244. It is much easier to add a bit more glue than to wittle down a ferrule. You might also be able to just plug the ends with epoxy but I haven't done this so I can't speak from experience.

Daryl