What's the baseline for just plain Big Money + Donate? Has anyone figured that out?
Donating twice is fast at rushing for the Province split, getting the 4th Province on turn 10, 11, or (rarely) 12. Compared to
donating once as per aku_chi, you probably have an extra Province after turn 9 but two fewer Silver.
Turn 1: Buy Silver *
Turn 2: Donate down to Silver + 4 Coppers
Turn 3: Pay off debt
Turn 4: Buy Gold
Turn 5: Buy Gold
Turn 6: Donate down to Gold, Gold, Silver, paying off debt **
Turn 7: Buy Province
Turn 8: Buy Province
Turn 9: Buy Province
Turn 10+: Buy Province or Gold or Silver ***
* Of course opening $2/$5 doesn't allow this. Anything else is fine, even $5/$2 repaying 6 debt on turn 3.
** You need 8 coin in hand to have no debt left over. The 1/7 of the time that you don't, you can only afford Gold next turn.
*** Before turn 10, your deck is 3 Provinces, 2 Golds, and a Silver, so a fourth Province is a 1/2 chance of a treasure being bottom-decked. If you miss, you have a 4/5 chance of Province on turn 11.