My quarantine process is similar to Option A listed above, with a slight variation. I don't like to medicate unless absolutely necessary; the only med I use for prophylactic treatment is Prazipro since it's one of the most gentle meds at our disposal. My protocol:
Day 1: New fish in QT with salinity matched to transport bag (I buy all of my fish online)
Day 2-3: Ensure fish is acclimated properly and is eating well.
Day 4: First round of Prazipro
Day 9: Partial WC, followed by second round of Prazipro
Day 14: Start TTM
Day 26: Finish TTM, observe for additional week (minimum) to ensure no Amyloodinium or Brooklynella is present
Day 33+: Transfer to DT
If velvet or brook rear their ugly heads, I cease TTM and treat for these parasites immediately (I have CP and formalin on hand as part of my "fish medicine cabinet"). If the fish is shipped at a low salinity (most online retailers ship fish at around 1.018), I raise the salinity by 0.001 during each transfer in TTM. I keep my DT at 1.025, so no extended acclimation is required when the fish is moved.