Sounds like you have it covered but just in case, you don't need optics (hardly ever), use the Deep Red 660nm, not the crees (those are 630nm), and if you are going to run some blues, use very sparingly and if possible try to run them at a reduced current compared to the reds, or if that is not possible, don't put 2 of them directly across from each other. You can wire 2 blues in parallel within the series string and they will effectively be a current divider (running at 350ma each). Like this r-r-r-b=b-r-r-r
Meanwell LPC-35-700 drivers are like $16 and can run 14 LEDs, no problem - go for the simple solution.
Instead of Royal Blues, you might consider Hyper Violet from Steve's LEDs - but they have a dome lens that has them at 60 degrees, but it's rather tall and you can slice the dome off halfway up if you are careful and get a nice 120 plus distribution.
For the array, figure out your screen size you are going to use (length and width) and then divide that by 8 to get the minimum number of LEDs, or divide by 4 to get the maximum. This will get yo uin the ballpark of what will work - choose a number that makes sense and is easy to arrange.
For instance, if you are making a 6x6 screen, that's 36 sq in, 36/8 = about 5, 36/4 = 9, so between 5 and 9 LED should be good. 9 is an easy array, 3x3, but you could do 2 rows of 4, etc. On the MakersLED heat sink you can move them around if you decide to change later.
If you use the higher number, you might add a diffuser while the screen is maturing, then remove it once the screen has grown in.
Also the MakersLED heat sink comes with a fan, you just need to get a power supply.