I have a micro-cell tower I use for cell phones at home that connects to my router that requirements are the same as my internet connection 1.5 DSL . I only use 50% of micro-cell max devices connected limit at most so giving it a min of 50% of my connection should be ok.
On dd-wrt I normal just give it the highest Priority over everything else to make sure it gets what it needs but I am unsure how to set it up properly on gargoyle so that it would work right .