Just buy a full spectrum led. You don't have to supplement it.
Two 39w t5's to supplement my two kessil a350's. I run them about 6hrs a day with the kessils running 9hrs so far. Since adding the t5's about a month ago, there's definitely a difference in colors! all colors actually! but most noticeably in reds! yellows! and oranges. Some colors have lightened up some but it could have been that I added kalkwasser, gfo and switched salts about the same time as adding the t5's.
I run 2 vega blues, with 2 36" t5s. Only added the t5s a few weeks ago so to early to give an opinion. Color and growth were not an issue as much as the shadowing from the LEDs, which is why I added the t5s.