David - do you have one of these multi protocol modules? I don't so how much software tinkering is there?
I do, I have the irangex STM32 v1 multiprotocol module (no switches/LEDs) -- it's really only suitable for OpenTX use with a serial connection (which suits my X9D+) as there is no pot/switch to select protocols. It needs to be done through OpenTX 2.2+
That's part of what I was referring to by software configuration. That part isn't any different from any TX setup, and would have to be done with the DIY Spektrum module as well.
The additional software comes, depending on which version of the multimodule you end up purchasing. If you purchase a sufficiently new module, especially one with a USB port, the software that drives the multimodule itself may be sufficiently new, or easily upgradable. My multimodule requires me to open it up, connect a FTDI interface to it, and flash new software from Arduino IDE pulling from the latest github repository:
https://github.com/pascallanger/DIY-Multiprotocol-TX-Module
As you can see from the commit history, Pascal makes fairly frequent updates. He's fixed bugs and made improvements in it that I deemed sufficiently worthwhile for me to upgrade my module with on a fairly frequent basis. I last updated mine about 2 months ago, but you can see that he's had updates from 10 days ago. They were mostly documentation updates, so I don't need to take it apart to reflash for those.
The newer STM32 modules with the pot/selector and USB interface would be well worth the slightly higher cost, IMHO. If you have a OpenTX 2.2 Taranis (for SBUS in the module bay), you don't need the pot, as all the protocols are selected by the TX menus, but the USB is handy for installing new software without the FTDI bit.
Hope that helps.