Today I threw together a spreadsheet which allows you to quickly determine if a rotation between players is feasible.

How to:

Download the spreadsheet or save it to your google drive. You will need to do this as it is not (to the best of my knowledge) possible to allow users to use the cell selection function on the live document without them being able to break everything else.

The magic happens at the bottom part of the sheet (This part: https://i.imgur.com/OnwCfcX.png)

Here you can select the two teams you wish to compare, and below them will be displayed the combined FPL-FDR ranking. In my opinion, this is especially useful for determining which budget goalkeepers can be bought and used effectively in tandem, but it can also be used for deciding on outfield players too.

You may download, modify, reupload, whatever.

https://docs.google.com/spreadsheets/d/1yelB-D7SDcTpl2waayPQZeixGHpsFw8sA-S7rLKo5Us/

If anyone has any issues, questions or suggestions, you can ask me here.

If anyone finds this useful, I will gladly update and improve it through the season. Perhaps a better version of this already exists, but I couldn't find it.

Edit: alternative positional FDR ratings added by request