B-3 + 145 setting: open, 8 ohm, 16 ohm?

[philduke@leland.stanford.edu (Philippe Ducor)]

This is a newbie question. On my 145 (=147 amp) there is a switch labeled
console load resistor with 3 positions: open, 8 ohm, 16 ohm. Which one
should I use knowing that I have a B-3, and that the 145 is my only
speaker? (it is now on "open" and the sound is real great, but I don't want
to blow the Leslie driver if the setting is incorrect...).

Thank you in advance

Phil