Hi, let me ask, just curious. Why in serie?
SFMI4UT
Because it mandates the required voltage of the driver. Series LED wiring will divide voltage and current among the diodes, thus needing 3x voltage and a standard linear regulator wouldn't work. Parallel wiring can use the standard forward voltage of the LED, which would allow a lower source voltage. However, any factory variations in the LED would sent disproportionate current (thus brightness), so you would likely need a resister behind each diode to ensure this doesn't happen.
Edit, to answer the OP's question (at least partly):
I didn't look at their drivers, but I can answer your question in theory. If you want max output, get a buck/boost driver capable of stepping up the voltage to 3x the forward voltage of the XPG LED (ball park of 11v on the safe side). Then, XPG's have 1.5A max current. Amps x Volts = Wattage. If the driver can triple the voltage and it can supply 1.5A at that voltage, then you will have a perfectly regulated max brightness driver for the three XPG diodes. Summary: you are shooting for 3x Vf at 1.5A current.