National Resophonic (NRP, for short) make the very best (replacement) cones for your Tricone and yhe two sets I bought are very high quality. After much experimentation of cone design and aluminium alloys, NRP came out with their new improved cone, in perhaps 2009, or maybe earlier, and call it their Hot-Rod version. The older version were STILL the best you can get, then they improvemed them a lot more !
I think the NRP Hot-Rod Tricone cones are even closer in sound to original Tricone National cones (from the 1920's and 1930's) than even the 9.5" single cones that they do for their own guitars (and replacements for old National cones).
The 9.5" NRP Hot-Rod single cones have a slightly different sound than the originals (but still very good), but amazingly, I hear far less difference with these Tricone replacement cones, other than they are LOUDER than the original cones, and perhaps a fatter sound too. The set of three cones were 2g lighter than the set in my 1931 roundneck Tricone and 3g lighter than my 1927 squareneck Tricone - so should be even more responsive. Tey certainly sound it !
I bought two sets of Tricone cones AND two 9.5" single cones.
The nest you can buy !
Packaged safely for shipping from Germany to Scotland and these delicate items arrived unscathed.