vettin2nite here should be a link for some retro kits. I'm having trouble finding the six foot retro but two 36 inchers would spec out the same as the 72" one I have.
Here one on the same sight if you wanted some MH
style lights but this will probably be overkill for a FOWLR
. Its a full 72" with moonlights.
Here is another website. Its at hellolights.com for a buil it yourself retrofit that you can use whatever you want in it . MH
Hey I hope these links work but I dont know if they will. First time doing this If they dont Pm me with how to do it and Ill redo it for you. HTH