No worries, my absolute pleasure.
So on the day of your medical, take police certificate, birth certificate, passport, copy of vaccination, and your case number.
If the other sponsor (the co sponsor) is willing to co sign your affidavit of support, you'll only need one. The embassy, will ask you questions about your co sponsor, so have all that ready. But you'll only need to provide one affidavit of support along with proof of income.
Tare care, and good luck.
lchopra got a reaction from Nich-Nick in Help! Lost with Medical & Interview at London US Embassy