If load time is the issue, you can also just set up the sheet to publish to HTML every 5 minutes. The only issue is that, when there's a ton of formulas, some of them get snapshotted while the sheet is still updating, but those you can just speed up by writing them better or writing custom formulas in GoogleScript that swap out some of the formula cruft for more performant code.
Anyhow, that spreadsheet is quite great - does the sheet.best thing mean that the sheet doesn't as-is? Or that it won't work (for free) once you hit some volume?
Btw you can probably also get rid of the need to manually trigger the sheet by having an Apps Script function run every few hours. (
https://stackoverflow.com/a/9129775)