As a Watchman Marauder i can affirm that Internal relic has around 15-20% crit chance, and elemental one has 40-42% crit chance, as I have 41% crit force buffed, i assume that your statement about force/tech users is correct.

So for force users BiS should be:

1. Dread Guard Elemental Proc Relic

2. Dread Guard Relic of Boundless Ages

So would I be correct in assuming that means for non-force users, ei. a Gunslinger, BiS would be:

1. Dread Guard Internal Proc Relic

2. Dread Guard Relic of Boundless Ages