I am using spectra 9+. I will use massage mode till there is a letdown then I will change to vacuum mode. If the flow is slowing down, I will switch back to massage mode till let down again.
I'm using spectra 9s. I will use the massage mode till i feel a letdown before switching to suction mode. On massage mode, i use level 4 to mimic the baby's suction for a letdown.
I use the spectra, I switch it on for between 1- 2 minutes before I pump. This helps to increase my let down.