+15 str. really expensive and at least not a noticeable change, at least not for my tyrr.
I am not sure if +3 con adds 1k hp I think that when I use my con hat is just like 600 could be wrong tho
Again +15 str, because in theory you might have the slight, random chance of a critical skill like those rare moments when you use your giant barrier and doubles the time; so far just once for me.
Best and most cost effective are:
3x Lv2 STR Legendary - if you're poor
3x Lv4 STR Legendary - if you're good with adena.Best choice overall, since in total you lose only 3 DEX, which frankly isn't much at all.
Side note:
STR also affects crit. dmg too, besides skill mastery and patk.There's also a break point in STR, which greatly increases your dmg.
Juji did a test about this. even his STR is 140, it does not make any "greatly increase"
Just some number to remember, 5 CON = 3k HP & 3k CP; 5 STR = about 300-400 P.attack on your stat
With Lindivor update, each tyrr have its own build and dye. I am a duelist, I will go for +15 CON or +10 CON +5 STR