I think the key is in the word ''draft''. I do hope you can come to an agreement without going the court route. Have you discussed mediation? To have a financial agreement formalised you need a Consent Order drafted, signed by each of you and rubber stamped by a court. Judges have to know that you each are in receipt of all relevant financial information (by completing form D81) and have taken legal advice, and that the split doesn''t leave one party financially compromised compared to the other.
If you are still worried about the paperwork then you could just send your wife a letter to say that the spreadsheets etc. are merely work in progress in trying to reach an agreement and do not constitute an offer.
Do you know how much more your wife is expecting to get? As said by maisymoos, if you give details of your finances etc. on here then someone will be able to advise on what a reasonable split, looking at it on a ''needs'' basis, would be.