Question is, "Does the "- to 3" toggle switch on the dash still adjust the beam like it does on normal lights? Just wondering in regard to carrying loads etc as it would be desirable for the perfect angle to be setup whilst on setting 1, then be able to select 2 or 3 if carrying heavy loads?

If you swap the level adjust motors over, Then yes!

Does the load leveller switch run 1-3, or 0-3?

- 1 2 3 are the settings, and yes they do work

yes