Pitching on yeast cake or start over and double pitch

I am going to finish up a month of fermentation on a S-04 yeast cake. This is the first use of that yeast. I am wanting to start another beer that is above 1.060, and they suggest a double pitch of WLP004. Do I need to double pitch or can I rely on the fact that this pack of S-04 is going strong in the current beer that there will be enough cells in there to take care of the next beer? Batch size is 5 gallons, and I used 1 pack of S-04 to start with on the last batch.

there'll be plenty of yeasties in the yeast cake for a 1.060+ batch. i pitch a 10g batch on a yeast cake from 1 pack on a 5g batch, and it comes out fine

Go for it. I do it often. Just be ready for some serious activity and it starts early. It's all good fun.