Well this is from Failure on BG:
Assume it's correct to use this thread as opposed to starting a new one!
Thanks to Muhnjob for testing with me since I didn't plan to make these gloves (though I may now).
Unkai Kote +1 Enhances Sekkanoki:
~1191hp Spirits Within
300tp - Sekka (gloves remain on for WS), 223 dmg. Equivalent to a 200TP WS.
200tp - Sekka (gloves for JA and WS), 186dmg.
200tp - Sekka (gloves for JA, removed for WS), 148dmg.
Seems that when you use Sekka, you gain 50% of the remaining TP as bonus TP.
Attempt to confirm:
260tp - Sekka (gloves for JA+WS).
Expected dmg = 1191/8 + 1191*.8/16 = 148.875+59.55 = 207~208 (give or take another few depending on rounding)
Result: 204 dmg
Close enough, I'm sure I'm off on rounding.
TLDR:
Unkai Kote +1 gives you 50% of the remainder TP as bonus TP on your WS, but must be left on for the WS for it to work.
So im sure they are going to beat out the +3 str you would get. And the +1 from alky.