[shilala]

I've never been impressed with big smoke-eaters, but most will say they're a must.
A make-up air unit that delivers lots of fresh air and a strong positive air pressure would be my choice.
I'm sure that by now there are air-quality sensors that can throttle the amount of fresh air to save energy. I used to build manual control systems that throttled the make-up air because there weren't any kinds of sensors, but that was lots of years ago.