This stems from a whole bunch o' Tachyon splicing for certification. We sent in a ton of splices for certification, all of which were done using a wire fid for the crossover.....the splices passed, but were not quite as strong as what I thought they should be...Turned out that two factors were in play affecting the overall strength.
Firstly, we were tightening the section where the cover bury and core bury come together a bit too much, resulting in a slight weakness as too tight of a connection acted as a shearing agent under massive load...
Secondly, for some reason using a hollow fid for the crossover results in less disruption during the crossover than a wire fid does....the end result being that the hollow fid crossovers tested out stronger..
Once we amended our splicing for Tachyon to include a slightly looser connection between cover and core as well as using tubular fids for the final crossovers we far exceeded the required strengths for certification by NER (the initial splices passed as well, but not by as much as our current specs)
I have seen Tachyon done a bunch of ways by a bunch of different splicers/companies. I would suggest sticking to the NER recommendations for this one... Many ropes can be manipulated during the splice to achieve extra strength, but Tachyon in particular seems to be a bit finicky with achieving the required strength after splicing.