I actually did make a stab at adding in rewards from BG tournaments to the ratio calculator, just forgot to mention it in the changes list, I think. Take a look at the bottom of the bank tab. Unfortunately, I don't think it's complete yet as I didn't add space for the daily rewards which has a lot more types of things you can get. It's a work in progress :)
As for copying from 4.0->4.2, that is something I hadn't really thought about until last night. It's tricky because you don't want to just cut-n-paste areas because the formulas might have changed.
For the bank page, you can safely cut and paste the following columns "Last Large Payout", "Overflow Killed (Credits)", "Overflow Number Rewarded (Debits)" from "Archer" through "Food". Be careful though because Reavers and Huntress were added, so you'll have to make sure the old values are in the proper rows on the new spreadsheet.
In order for the bank to be correct, you'll ALSO need to copy the "Previously Accumulated Totals" columns on the Defensive and Offensive BG tabs. You'll need to grab the rows for "Own Units Killed" and "Rewards" ("Initial Enemy Units" and "Enemy Killed Rows" are optional - they're just fun data to know). Again, be careful to make sure the values get copied to the correct new rows because of the addition of Reaver and Huntress.
Edit: to more easily determine which places you need to copy, I've modified the 4.2 version to have the cells that you need to copy have a light orange background.
For all other pages, you should just be able to safely copy and paste any cells that have a white background.
I'm not sure if there's a way to automate this - there might be. I'll give it some thought and see if I can't figure out a way. For now, those instructions will have to do.