I also just upgraded to a 75 and was about due for 4 new bulbs so i decided to get the Chinese LEDs and turned all the way down they almost match the intensity of the t5s there really is no comparison how much better the corals look. I paid 230 for two panels so only 2 more bulb changes after this one or maybe 18 months I have recovered the cost. Cost aside they look way better I wish I would've done it sooner and now I can support anything I want (at least from a light stand point).
The light doesn't affect the nitrogen cycle so you have time to look around and gather research before you upgrade.
Definitely get the test kits if you haven't yet.
Now that I've thought about it you really don't want to rush into corals anyway so if I were starting new (and on a budget) I would keep your current lights and get the rodi
unit first then do the light upgrade later maybe in a year.