Writer's Leaderboard

I run a writer's education website. We have "bootcamps" where each writer logs the word written each day. I would like a leaderboard that captures entries that users record in a Google form, then totals words written and av words per day, then displays them in a leaderboard format. I would prefer using google forms for capture and google sheets for calculations and display. The form also needs to only allow numbers for dates less than 3 days in the past so should not accept any entries older than that. I have mocked up the form here: [login to view URL] This form captures the information in a google sheet which I would like to use as the source for this leaderboard. We will know the names of the participating users so we can pre-populate them in a dropdown in the form. Or if possible put them in the spreadsheet and validate against that we usually get between 40-100 users so that would be a pretty big list. The leaderboard should allow us to show the username and pull an image from their profile on our Xenforo forums in their profile. It should show the name, image and the # total words and #av. daily words with the leader (total words) at the top.