Making TANDEM/TWIN Function Switches more useful in ETHOS

 The TANDEM and TWIN radios have 4 or 6 Function Switches rather than the 6-position knob that the Horus radios come with.

These Function Switches can be set up one of 5 ways on the TANDEM's (I don't have a TWIN radio yet to see what the 4 switch configurations are)

6-pos with OFF
6-pos
2x3-pos
6x2 pos
Momentary.

However they CANNOT be used as sources. I'm going to go over how to get around that limitation. This is most useful for those looking to replace the 6-pos knob as a way of controlling FC Flight Modes, but there's a laundry list of other uses which effectively give you between 1 and 6 extra switches on your radio.

The solution, in short, is a VAR mix. Just one, although you can have multiple sets if you really need them. I'll go over that last, as there's 2 ways to achieve it and neither are obvious as VAR mixes cannot be enabled/disabled unlike other mixes so you cannot have 2 VAR mixes outputting to the same channel, selected by switch or flight mode. 

In short, what you do is the following.

We'll do this for the 2x3-pos configuration, as that covers the logic for all of them.

Create a VAR Mix, Name it 'Left FSW'
Add a new weight, tap the '---' box that opens up on the left line, press FSW2 (the middle left button), then set the weight to 0
Repeat that with FSW3 (the bottom left button) and set the weight to -100

Select an empty output channel, I've picked Ch64 in this case, then let it rename the channel.

Now anywhere you want to use the switches as an analog source, use Ch64 instead. It's even conveniently named for you to remember.

For the right switches, just do another VAR mix named 'Right FSW' and targeting a different channel (say Ch63). You can actually clone it to reduce time.

In terms of the number of lines you need, it's one less than the total positions, so:

6-pos with off - 6 lines total, one for each button
6-pos - 5 lines total, one for each button except 1 or 6 (your choice)
2x3-pos- 2 lines total
2-pos & momentary - 1 line total (remember to hold down the momentary when exiting selection so it does not reset)

Now for the hard part, how to have Multiple sets. 

There's two ways to do this, and both are kind of stupid. 

First off, create the second VAR mix by cloning the first one, renaming it to be clear, adjusting the values and setting a different output channel. By cloning you ensure you are using the same table selectors (ie the FSW buttons in this case).

Then you need to make the new mix override the old one.

The first and easiest is to add 1 Free mix per VAR mix over 1 you have. 
Set the source to the channel of the new VAR mix/value table
Set the active condition to the control you are using to select the VAR Mixes/tables (this can be any switch or LS, for Flight Modes leave the Active Condition as Always On, then edit the FM table for the free mix to select the FM's you want that one active on). 
Set the Function Type to Replace
Set Output1 to the channel of the base VAR Mix/table.

The second method is a bunch of dumb, but it works. That's to make a set of Logic Switches that are true on FM/selector position and table selector position (ie an example would be FM1 AND FSW3), then add those as additional table entries on the VAR mix. I don't recommend that solution unless you are running into issues with a lack of channels available for mixing, which is unlikely even on complex setups.