As market turned up at the intermediate term, my option premium selling portfolio for December has been dealing with rising delta. Yesterday as time was gradually get closer to expiration, I found it's helpful to create a regular butterfly spread which increased theta and reduced delta for the smooth portfolio. The main effect appeared to be pumping up the right slope of the P&L chart from 1430 to 1440 area as shown in the image below. When the 2 to 3 day pullback is done, I might have to purchase 100 or 200 SPY to neutralize portfolio delta by 10 to 20 points, weighted on the SPX index. It should keep my theta around 100 for a few more days so that I can close the December portfolio about 2 weeks before expiration.