Thanks everyone for the help. I've been continuing my research and have run into another road block.
Assuming I buy the two meanwell dimmable drivers (HLN-80H-24, which I've read that the other common meanwell dimmable driver ELN-60-48 you cannot use less than 8 LEDs which I will have 6 XMLs on each driver)
Datasheet is your friend.
Voltage output range for this is 14.4v to 24v, which means your XML's (which have a 3.5vf at 3.0 amps) can be 4-6 per driver. I'd definitely put the full 6 per driver.
do I need to buy another component to dim the leds? I've seen a meanwell dimmer?
This one does not appear to be "dimmable" in the main sense of the word. You won't be able to easily dim it up/down to play with light intensity or anything. You'll need to look for a model ending with "D".
This model will have an internal screw that allows you to set the final current, but it's a hassle to get to if you want to dim the LEDs a lot. Meaning, you set it and forget it. And you can only go down to around 2.0amps, which is still brutally bright.
"D" models require a small voltage input that DOES NOT exceed 10v. Anything from 7-10v will work. Once you hook up your voltage (small regulated DC adapter) and a 10K potentiometer knob, you can then turn it on, measure current, and fiddle with that INTERNAL screw I just mentioned to fine-tune your current output.
Good luck finding a D model for this Meanwell model.
From what I've read, you need to have at least 3 drivers connected to the dimmer, where I will only have two.
You're thinking of the RapidLED "pwm" dimmer. It's a specialty dimmer requiring a specific version of the dimmable Meanwell drivers (those ending with P).