The electric sky has long been a peeve of mine; they have a very interesting flower spectrum based around phosphored whites, but instead peaking in 600nm like a normal 80cri led, it peaks in 660, which has peak flower response and has a fat tail towards the far red covering those hard to get at 680-700nm which are almost impossible to cover efficiently.
A couple of things though: almost no blue, this will make it harder to vegg, especially if you have low heat and not perfect environmental control. Another thing is watts: 2x300w is generally on the low side of flowering a 5x5. I would maybe add a way to add some blue and some more watts to the mix. OP, if you wanna DIY you could do this as an add on: if your main thing is spectrum correction id look into the bridgelux vesta strips, they have both 5000k cold white and 2700k warm white, to add during vegg and flower. About 150-200w, 6-8 strips on alu u-channel, well distributed and you should be golden.
It is easy to diy, but not the es- spectrum, those are some really special diodes....