Tent re-proofer? Any recommendations?

[3MonthMaid]

Hi, I was hoping to waterproof my tent a little more by giving it a spray with re-proofer.

I definitely want to spray rather than paint it on, ideally as non-toxic as possible.

I have looked at nikwax before? Would that work?

Thank yiu,

Fabsil has always been good but only used the paint on I think they also do a spray.