Performance PowerBi. What is the most optimal?

Syndicate_Admin Alexx95 

Wow! Lots of great questions. You may get better response if you post them as 3 separate questions, as they are different enough that different people may be required to answer them. I don't have all the answers but will try.

1) In my experience it's better to push the transformations back as close to the source as possible. So creating views in SQL and pull those into Power BI is best. 

2) This is a tricky one and it depends. How much of the dataflow is used in each report? How much overlap is there between reports? Keep in mind that when a dataflow refreshes, the entire thing must refresh or if one part fails the entire thing fails, so may be better to split the data flow into 'core dimensions' that get used across most reports, and then put the other tables in another data flow or dataflows. 

3) How does Form A relate to Form B? Not knowing the forms, I'd guess that User relates to Form A and User relates to Form B but that form A doesn't relate directly to form B. I need more detail on the forms though to confirm that. 

For the different users (created by, modified by, approved by, etc) you can use role playing dimension and inactive relationships, or you can have an 'approvers' user table and a 'creators' user table. This also depends on your desired end result -

do you want to see how many forms Jorge created and approved in the same visual? then use role playing dimensions

Or do you want to filter by Jorge as an approver, and then filter by the creators in a separate filter / visual - then use approvers and creators separate user tables.