Rule of thumb is about 5 luc in pvp cancels out 1 luck on your opponent. In other words, 500 luc on your toon negates 100 luc on theirs in pvp. This becomes a bit of a problem if you try to sit around 500 luc, because you're essentially only fighting with 350-400 Luc, limiting your crit rate. However, the majority of players do not have immense amounts of luc to negate all your crits. The average luc build player has about 1k - 1.5k at best, and if they know how to balance their toons, they are lower.
Str Adds 1 Attack
Luc Adds .3 Attack + after attack calculations of (random # from 0 -1.5 per luc)
If you do the math with an ele I factoring of .5 to 1.4 times damage, to a weak ele, You'll find out if dex is contiguous, and only str and luc move, Str and Luc Builds Both have about the Same maximum damage.
The Luc Build will have a lower minimum damage than str though, so for averaging damage str is better. For rec builds, the luc would be better.
However, On Ele II, The Damage Factor Increases by 1.8. That factor is not reflected in the second part of Luc's damage contribution, because it is added after defense calcs. This makes Str by far more helpful, because the Ele II affects the damage wholey.
I say 600 -800 luc from linking, Full str after 900 dex. That'll make you a pretty decent build.