Since you are doing a 3-4 month cycle, once it is complete, I think it would be good to start the refugium. It is important to not start a refugium until after the tank reduces the ammonia input (usually 2ppm) to nitrate within 24hrs, because the macroalgae can throw the cycle off. After you complete your cycle and do a water change, you will still have nutrients in your tank and that should be sufficient to start the refugium off with. I would advise you to keep the display lights off while you cycle and even after until you also establish the refugium and some utilitarian fish. After you start the refugium, I would say you are at a good point in adding some hardy fish in there. Adding fish within a close margin of time from the starting of the refugium would be a good idea so that you will have nutrients that can be utilized by the macro.
As far as dosing Triton Base, I would hold off on that as you will not have the uptake from coral and other consumers that will be making dosing necessary. And also, the supplements are rather strong so until you are seeing alk and Ca being consumed, dosing the additives will just cause accumulation and raise your levels.
What salt are you using?