A question for those who have one, or who have used one.

I bought one of these on ebay, and it came with filters in the swinging
"door frame". These filters were red and had red tape around the
filter. I noticed too, however, another filter just below the swinging
door sitting in the 'framework'; in the unit body itself. This filter was darker and had yellow
tape around the edges.

I went on B&Hs web site and they have replacement filters, with
red, black, yellow, green and blue edges. It wasn't clear to me that
the filters that were in the framework below the door belonged there,
or were there for ease of shipping. So my questions

1) Are there supposed to be 2 sets of filters in the safelight; one in the door and one in the unit/framework?

2) If not, isn't it harder to control the light if there is no filter between the [open] door and the bare bulb?

3) From reading B&Hs site, it would appear that the yellow edge,
and then red edge, are the best for standard B&W work. Is this
true? What have you have you found to be best?

4) Any other input is appreciated.