Awesome Cab dude...
Because of where I live, my humidity is also around 65% during the
dark period...My cab used to be as crowded as your's, and I suffered
some bud rot due to lack of air-flow. I have since added a better fan,
and air out the room as well as possible. I haven't had any problems
since, so I decided against a de-humidifier. If you have the money
though, go for it...
Once those buds start forming, try to tie them off at least a foot from
that light...You could consider trimming some leaves for better light
exposure also, just do a couple at a time...Good Luck.