Bookings Logo Help

I see there are a number of different previous threads re: bookings logos. Please can someone from Microsoft reply re: what size logo is suggested for:

1. The main calendar view from the business side
2. The public facing customer logo size (which seems to be about half of 1 above?)
3. The email confirmation to customer logo size (which seems be be about half of 2 above?

In all other Microsoft apps you are advised the best logo sizes but numerous queries on this have received no response. Also any preferential browsers for 1 above or image formats? Please answer Microsoft!!

Teja Vinukollu