Never gel the front of the camera. You can use filters but not gel.
In side this shop are there any windows and any daylight to consider? Before you consider any color correction to your lights you need to consider the areas you can’t correct and work to match that. And if there is are you shooting during twilight as the ambient daylight goes away? I would think the architect designed this room with lighting in mind and as others here have said there are many color temperatures of T-8’s. However the maintenance man probably doesn’t give a hoot to color and the room could be a mix.
In my opinion the Philips T-8 TL 900 series flos are the best film ready tubes on the market. I use the TL 950 for daylight and the TL 930 for tungsten balance in my package as a Hollywood Gaffer every day I work in film production. Together with the Advance (Philips) Mark 10 high freq dimmable ballasts they are incredible to work with. I have made my own units with Kino flo housings and have worked them for over the past 8-10 years.
If you need to color correct look at the big picture and see what you can’t correct first, then correct to it. Balancing the camera to a custom setting can help too. I believe knowing what color temp you are working with is extremely important. If you don’t have any daylight then changing the tubes to TL 930 (3000 Kelvin) and balance the camera to incandescent.
Good Luck
Michael Palmer