Global Data - Year over Year report of total leads/contacts

Hello community!

We recently experienced a major change in our Dynamics CRM which merged all people to a single object table - so we converted all Lead records into Contact Records.  We now track changes in engagement via lifecycle stages in the CRM tool.   Given the change, I was asked to provide a couple of key data points so that we can take a look at the effectiveness of the switch at a macro level, namely: 
1. A YOY look at total number of lead records in Act-On
2. A YOY look at total number of contact records in Act-On

Has anyone found a way to produce what is essentially a "snapshot in time' of the total number of records in Act-On at a specific date in the past?   I got some good starter guidance from the help chat, but it all boiled down to only being able to see created records on a certain date.  That's fine, but not an accurate report of ALL records that existed in the system at the time. 

We tried some workarounds in both Data Studio and using segmentation, but the results still didn't quite get us the full picture.   Would greatly appreciate this kind of global data reporting for this request, but also things like user domain comparisons - what percentage of our total users are coming via gmail vs yahoo,  or account-wide email performance -  what are aggregated numbers for average opens and clicks for all sends in a YOY look). 

My main issue is that when I try to collect large data like this, our account quickly maxes out our token use in Data Studio, which we need to run some daily reporting.  We have limited budget, so increasing tokens is currently not an option for us.    

All suggestions appreciated!

Thanks, 

Ginger Eastham
Growth Marketing Manager