Need help building reports on client Usage!

Hi! I am trying to see if the Formula fields in report builder will accomplish this or if I need to create a new MDA with custom fields.



The goal: I'm trying to find the % of users that are logging into our platform via our Mobile app OR % of users not logging in 45 days+ (2 sepearate reports, but I think the same solution could be applied to both).



I have a field in our usage MDA called the '1st Mobile Login Date', I think I could use this as the identifier - that if this field is populated, that the user has logged in via mobile. With date ranges, I could possibly alter this to be something more dynamic, where we could then adjust the % of mobile users in the last week or month, etc.



However, the formula fields have to be setup the correct way and I am not quite sure how to get '1st Mobile Login Date'/# of Licensed Users' in the formula to then generate that percentage. I'd rather do this in GS instead of outside the system and then pumping it in but am struggling a little bit.



- The same method would probably work on the other report request: where we have the "Last Login Date" field that could be utilized for finding % users that haven't logged in for more than 45 days.



OR would creating a bionic rule that calculates this be better OR we could do this in the MDA itself?



What would more experienced/technical people recommend here?



Thanks again for all your help!!