Screwdriver you're insane! You're going to make an electrician out of me in no time. So, my constant current drivers keep me from having the heat issues you're talking about? What's a good brand multimeter? All I have is a cheap one from harbor freight.
No,no,no. Well, maybe in a roundabout way in the last no. By using the constant current power supply of 600mA you have restricted the amount of heat that will be created by the LED. Also, the heatsink has sufficient surface area and a fan to dissipate alot of heat. So in your case, yes, using that 600mA constant current driver is keeping the LED light cool. BUT, if you used a 1500 mA constant current drivers, you may not be able to dissipate enough heat with that heatsink and fan. Then the LEDs run a little hotter causing possible damage. Many benefits to keeping the LED cool.
With most stuff, the cooler it runs the better. Including the drivers.
In the LED driver for the first string . The output max is 48vdc @600mA. Working at the max power it will put out 28.8 watts. Lets look at the input, 110-265vac and .2 amps. Which works out as 24watts. Well, the above math aint cool, input 24watt, output 28.8watts. You can't have more output than input. So, I assume it to be about 24watts power in that package. Do you want to use it at its max rating or do you want to dial it back a little? I think of heat, if it will be in some cooling path, is there other little heaters mounted near it, whats the ambient temp where it will be located. A bunch of stuff. Maybe I would drop it to 80%. That 24 watt power pack now is used at about 20 watts of total output power.
The second driver, max output of 27watts. We have missing input information to help us decide. So I can guess a max of 25-30 watts. Other information: Some thermal specs TA:50c(max), I take that as the maximum ambient temp this thing wants to live in to work right. 122 farhenheit. (Whats the temp inside that sealed black box mounted on top of the light where the temp is highest on the light) With assumtions of heating the max output of the driver drops to the 25watt mark for me. And 80% of that is 20watts.
The above is just my start guess design, by the time the project ends I would expect the design to draw about 40watts of power for the lights. An extra 10 watts to generate the 40watts. Plus an extra 5watts for the fan. For a total of 55watts from the wall. That should be about 2.2 amps draw on that house circuit.
I think your design uses a little more power. My guess is 56.88watts total power to run your light with 41.88watts of energy going toward making light. Of that, most is still heat.
Your little heaters can put out more light but they will get hotter.
Meters. If I was rich, I would get a Fluke. I like how the name sounds, I like the colors they use in their design, I like the shape and features. They are far more accurate than harbor freight meters. If you get them calibrated regularly and take care of them. I buy cheap harbor freight, or the Depot meters because I don't need 3.5 decimal accuracy or anything fancy. I just need a semi close indication of accuracy.