Am I right in thinking that V1 comes preset with low/medium/high modes with the other 3 giving you the ability to set your own low and medium settings?
That's correct. However, I can install another part into the other 3 if needed which gives you all the regular modes at the cost of max output.
The SST40 would drop to 1600 lumens
XPL HI to 1100
V2 to 1000 appox.