Need some encoder advise

I have been thinking a long time about building a simple rotary encoder device for changing the OBS and heading bug on the HSI.

I was going to use one of Hagstroms simple rotary encoder boards, but I don't know how to order the switch.

This site: http://www.digitran-switches.com/specsheets/57VLP.pdf
has what I think I'm looking for, but at the bottom of the page the ordering scheme is a bit confusing as I don't know what to order except that I don't want any stops and it doesn't have to be Mil-spec rated and I need a small index angle, and break-before-make (no-shorting).

I chose these because of the very low profile and they will have to be mounted in a very thin enclosure and mounted under the HSI Collins Pro-Line instrument bezel right on top of the panel. There is no room behind the panel.

It's also possible I might be able to mount the two switches into the fire rack.

The three giving me trouble are:

How many decks do I want?
How many poles per deck do I need?
What sort of output do I need?

Each switch is only controlling one function and only needs a left turn and a right turn output.

Anyone know what I need to order?

I ordered and am using these encoders from Mouser. The first part number is for a press on knob. The second is for the encoders. I liked this encoder because it can be panel mounted (has threaded output side with washer and nut) and also because it is very thin and wiring is into the side rather than back so it can fit in a very thin space behind a panel.

Knob (note- this one is black with a white index pointer)
550-P82-90F
Neutrik/RE-AN Contro
BLK .63"X.57"X 6MM

Encoder
688-EC11B15202AA
ALPS Encoders
11mm 15 RES 30 DTENT

I am using these for my Heading Bug, VOR OBS's, Altimeter, etc. I am interfacing using Desktop Aviator (www.desktopaviator.com) Rotary Encoder Board (2090) which is very inexpensive and versatile. It will give you up to 6 Rotary inputs. They also sell rotary encoders as well. Steve at Desktop Aviator is great to work with.

For my setup I am still testing some things. One issue I am having and am trying to work out is that if I rotate the knobs too fast, some pulses are missed. This is probably more of a tweaking issue. Note that you will need Registered FSUIPC also to assign the rotary inputs to the desired controls in FSX as these are not available directly in FSX settings.

I also have a Hagestrom KE108 board for most of my switches which also works great. It comes with 2 Rotary Encoder inputs and I am using those with my GPS panel for its dual rotary knob (I got this dual rotary from GoFlight Inc. (www.goflight.com) but they are also available from Mouser).

Hope this helps.
Scott