MS Exchange 2013/2016 - Sizing questions - anyone with experience on SSL-TPS with 500K users?

Hello DevCentral community -

I am looking for help sizing a MS Exchange environment with 500,000 users. The F5 would be performing LTM, offloading SSL with 2K certs. Application traffic is everything Exchange related - so, thick Outlook client, OWA traffic, and mail applications (POP, IMAP...).

Does anyone know what we are talking for SSL-TPS w 2K certs for a user base that large?

From this - I am trying to extrapolate the required equipment. (IE. a Viprion B2250 blade can handle 44000 SSL-TPS with MAX SSL license... is this enough? too much?)

If anyone has experience for sizing, estimate figures, horror stories, please share.