1965 spotlight question

[nhtc33d]

I am in the process of trying to mount a NOS spotlight kit on my truck.
When i put the template where it is to go it looks like when i drill the hole it is going to come out partially in the dash and the pillar? I dont know if that is correct place for it to exit. Does anyone have an interior picture of a mounted spotlight? I have attached a pic of the pattern where i think it is supposed to go. At the right side of the pattern it says "Place in bottom of drain trough" Any ideas where that is? Thanks for any help.