I wouldn't blame CFL's for anything, but they are the wrong thing for this tool.
I would say they are unlikely to work in a satifactory way in this type of printer. The exposures will be far to short for the CFL type bulb to even out into any type of consistency, even warmed up, because they are many many times too bright for modern paper, in this type of printer. (Unless you have a AZO stash, and you'd be nuts to wreck a bunch of AZO tying to make the CFL's work.) My "experiments" with CFL's in a diffusion enlarger also indicate uneven spectral distribution that mimics the spiral of the bulb, a sort of spectral phasing that casts alternating green and magenta spirals, so contrast will be all over the place on the same print with VC papers, even if you could get them on and off in a consistent predictable way, if your experience turns out like mine. The proximity of the bulbs to the diffuser in the contact box will likely exacerbate that problem. I found that I could get the CFL to come on in an "sort of" predicable manner if I pre-burned them for a few minutes, and struck the lamp within about thirty seconds. Not much time to get paper in and adjusted, and if you don't make it, you get to put the paper back and start over. (except these bulbs are gonna fry your paper anyway, unless your negatives look like a welders mask)
Not worth the PIA,even in an enlarger, where the output power was at least in a useful range.
Find 7.5w tungstens, and double diffuse, as suggested, or look into LED. The small output of an LED might be ideal in this application, and since you can get them in edison base, and you can get them in colors, and your going to rewire it, you could have two switches, one for green, and one for blue, and have a ready made split printer.
That's what I'd do. (Unless I'd been drinking)