What size uv box is useful?

I am building a uv exposure box. I initially need it for a project that will fit on a 100mmx160mm pcb. I will obviously design it large enough to deal with this project.

My question is what size should I build the box taking into account possible future projects that I am likley to embark on. What size is your exposure box and what size would you feel is necessary?

I think I would let the lamps dictate the size. But, I think the standard panel is 18X24 inches so I would make it at least 1/2 panel 9X12 inches.

I am using 60 UV LEDs, and on a euro board, I have an exposure time of 55 seconds.

I don't use a box, just avoid direct sunlight, no problems at all, works perfectly.

Easy enough to space the LEDs out a bit more, double the number for a bigger board.