Theres no doubt the pre-fab seal kits will work as perscribed. They are pretty pricey, so it really depends on your budget, and needs. Ive used them (door sweeps) at Normandy sound, but i can say with age (35+ years) they dont exactly work smoothly. The drop seal isnt perfect. Im sure lubrication would have help even more, but just working them loose got them moving "ok" when i was working on the doors during the re-build.
For the door seals, on the triad wave cave, i built them as described in rods book. I did however use a single seal, rather than wonderful triple seal in rods book. This was because we didnt add mass to the solid core doors.
For the weatherstrip we used GM type K, trunk rubber. It was available from "facca fasteners" supply company, and possibly elsewhere now. At one point it was tough to aquire. Its extremely durable, and looked brand new 5 years later, standing up well in the commercial studio.
For the threshold i just continued the door jamb style using 1x4 (ripped to width) jamb and stops.
I was concerned about tripping, and knicks and dents, but it proved not to be a problem on any of the 5 doors in the studio.
Had i used a double or triple seal, then i would have used a gasketed threshold, a drop seal routed into the door bottom, and door sweep, since a triple seal on a threshold would be quite tall.
Ive seen rod reccomend regular ribbed weatherstrip as an alternative to the magnetic weatherstrip in the book, for the third seal.
If you end up going rods method, i can write out how to install the jambs and weatherstrip, as rod told me on RO many years back. He doesn't describe the process in the book.
At the end of the day you just need something that creates and airtight seal, and is durable. The durability is im guessing one of the main reasons behind using trunk rubber, vs standard dept store exterior weatherstrip for the primary seal(s).