Driver selection for high power LEDs
Rather than three strings of eight LEDs I would use three sets of 3 LEDs in parallel wired in series.  This would balance the currents much better.  Powering three strings of eight LEDs would require three separate drivers otherwise the currents would be unbalanced. 









UPDATE


  I can only use 9-12V as input for this unit  


Use 4 series parallel sets of 3 LEDs (3P4S) x 2.







A very simple way to power the LEDs is with a Mean Well HLG-100H-24B  AC powered LED driver. With this Type B you use a 0-10V PWM signal.



UPDATE

I still think the best is to have a single serial string of LEDs.  If you can only use a maximum of 12V then I still recommend a CC driver rather than CV.  

For 9-12V use need 2 or 3 parallel strings. To keep the current balanced in each serial string you either use a separate CC LED driver for each string or use a single CC driver and balance the current through the strings.

The way to balance the strings is to use a Multi-String LED Current Balancer for Use with Constant Current Power Supplies such as the Texas Instruments LM3466.



If you think you can run multiple strips with a single CC driver add a shunt resistor to easily measure the current in each string.  I guarantee the strings will not be balanced.  At least you can measure how unbalanced they are.  I have seen where two string are driven in parallel the current mismatch was typically between 30% and 50%.  I have seen them go into thermal runaway.  This was using Lumiled Rebel LEDs from the same reel.





This is a fairly simple and inexpensive 350 mA, 95% efficient, Buck CC driver.
Use TI's WebBench to optimize for max current, input voltage, and output voltage.









The Lumidled CZ Line is not very efficient.  You may want to consider a cooler alternative.

The Cree XPEBBL-L1-R250-00302 has better efficacy than the Lumiled LEDs. 

The Lumiled CZ Line 470 nm blue has an efficacy of 22 lm/W (twice the heat of XP-E2)
The Cree XP-E2 473 nm blue has an efficacy of 45 lm/W (50% less heat than CZ Line)
Or you could use 24 XP-E2 and reduce the current to where thermal management would be much easier. 

You could use twelve XP-E2 LEDs for the same luminous output @ 350 mA as 24 CZ Line LEDs.