I also have the VAC Ren. Sig. Mk. III 140's & tried very hard to find 16 Golden Dragon 300B tubes.
After about 5 months of only finding a total of 4 NOS Golden Dragons - I opted for 2 matched octet sets of WE 300B's @ $5,800 ($10K List) & am much more than satisfied.
I think the KR 300B's should work very well & would love to hear the final results from you.
BTW - KH @ VAC now sells his own brand of 300B's @ $370 per pair.
After about 5 months of only finding a total of 4 NOS Golden Dragons - I opted for 2 matched octet sets of WE 300B's @ $5,800 ($10K List) & am much more than satisfied.
I think the KR 300B's should work very well & would love to hear the final results from you.
BTW - KH @ VAC now sells his own brand of 300B's @ $370 per pair.