No problem! First, let’s assume the lift time for your shells from launch to burst is 2 seconds. Now we’ll add in the 6 seconds of visco burn time which gives you a total prefire time of 8 seconds. Now it’s just a matter of writing the VDL like this, 1.75″ 8.00 PFT 6 DLY 2 LFT Red Peony Chain
8 PFT = 8 second prefire time
6 DLY = 6 second (visco) delay before launch
2 LFT = 2 second lift time for the shell
2 LFT + 6 DLY = 8 PFT
In a standard case, there is no visco so you can just use PFT alone. But in this case, the prefire is not just the rising time, it also includes the visco delay. So you enter the total PFT and use DLY and LFT to specify how the time is split between the visco burn time and the rising time (i.e. lift time).
