My grid looks like this:
I don't use the defender bow and lance except as mainhands.
XP isn't really an issue if you farm Advent Ultimates regularly (SR weapon enhancements are huge XP wells, and you can end up with dozens of them). The limit breaks are the primary bottleneck, not the XP. Also, once you're strong enough to farm Ultimate reliably, assault skill is likely going to be your main bottleneck on damage moreso than base stats.