I can say for certainty that there is no discernible color change in the vast majority of LEDs when you dim them, unless you grossssssssly overdrive them (then they turn "angry blue" and then usually pop soon afterward).
I've watched Cree XPG, XPE, XRE..... Rebel.... Bridgelux...and import "chinese" ebay LEDs...... on a spectrometer with the entire light spectrum graphed out in real time as we took spectral readings for them.
Regardless of the current level, the spectral output (the ratios) remained remarkably constant. Meaning, the graphs maintained the same basic shape very, very, very well.
See this graph on a Cree XML for instance, from 700mA to 3,000mA.
different dimming types I guess. The P versions use a PWM dimmer, so if you have a reef controller, you can hook it up to that to do on the fly dimming and other features (sunrise/set, lightning, etc).
The D version I'm guessing you need to build a manual knob (not sure, never used D only P)
Many Reef controllers like the Reef Keeper Lite and Elite (with the ALC module) do not use PWM but rather use 0-10v analog.
Rapidled.com sells a nifty pre-programmed PWM controller for a complete dusk/day/dawn cycle built into it. Very nice. Not cheap, but awesome.
Edit to add that you will need a 10V AC adapter and a potentiometer if you order the kit.
The nice thing about the Meanwell is that you really only need (at the most) a 6-volt power adapter (DC). The Meanwell has an internal plastic screw labeled SRV2 that can be adjusted to change the final current output.
Meaning it's entirely possible (which I have done on 5 different Meanwells) to use a 6-volt scrap cell phone charger and still get a solid 1,000mA out of a Meanwell.