When to use a 320 grit whetstone

[timfish]

OK,,, I have made a few knives and a bunch mistakes... Learning from most of them.. Lol
I mainly use a belt sander to shape (100-220 grit) and put a rough edge (400 grit) then 1000 for final edge then strop wheel
I bought a tormek knockoff,, with 320 whetstone
At what stage do I use it?
After 400 or 1000 grit stage?.?
THANKS

 

[os_tempore]

It'd better to go by the micron size. The go in line.

If it's about the same as the 400 it might be a needless extra step.