I think the length of time "required" to acclimate your fish depends entirely on the differences between your water parameters and that which is in the bag. For instance, the LFS
I have closest to me, keeps their tanks at 1.019 , my tank levels are 1.025. It takes me roughly 4-5 hours drip acclimating them. My shipments from liveaquaria take around 2-3 hours. Unless you check the water in the bag for differences in salinity and ph
, you really cannot just say "one hour is enough, 3 hours is too much etc..."