One way to really come to grips with mixing single mic impulse response (IR) WAV files into a mono mixed impulse response (IR) WAV IR file is easy, in terms of mixing your own cab mix.
For my Kemper Amps® users of Dr Bonkers cab files, here are some helpful tips to get the most out of my impulse response files.
Kemper® CabMaker™ requires the impulse response file to be wave files (.wav format), sampled at 44.1kHz and either 16 or 24 bits deep.
So use the 44.1K 24B folders.
I would try HypeReal ir mix files first.
Then Choice Mixes files next.
If you don’t like those, figure out which mixes you liked the most and use the MicDi single mic files.
If you find you need more bass, use the Power Amp single mic files versions for the same mics that you liked from the mix files.
If you need more instructions for using Kemper® CabMaker™, please see: https://www.kemper-amps.com/forum/index.php?thread/33850-cab-maker-manual/
To combine the single mics into a single IR wav file, this is not something that Kemper® CabMaker™ currently seems able to do. So you can either use your DAW to mix them together or you you can use a WAV based IR utility such as IR Workshop, or mixIR2, or Pulse.
Record your Kemper® with the cab turned off to your DAW. Yes your amp only recorded track will probably sound strange and/or offensive as most amps sound when there is no amp hooked up to them.
Use an IR loader VST plugin (such as IR Workshop, or mixIR2, or Pulse) to load the individual single mic files and mix the volumes, while playing your looped Kemper® track (make sure the VST is active in the playing track).
Once you find the mix proportions of the mic files you like, you can make the mix using one of the programs that I previously mentioned, or make the mix using your DAW in a separate session.
Just make sure the output impulse reponse (IR) WAV mix file is mono 44.1 KHz 24 bit, so that Kemper® CabMaker™ can convert the file with no problems.