So I'm working on a song where the main guitar part is played on an old jazz style arch top, F hole electro-acoustic with a single neck humbucker. I've recorded it with a single condenser mic on one track and via the pickup/amp on a second track simultaneously. I used take lanes on both tracks to record 5 takes. Does Splat's comping feature have any handy features or are there any useful tricks for comping across multiple tracks simultaneously in Splat?

Yeah... you have to use the grouping when you record it. When you do then your comping works collectively.
 
Preferences > Project > Record > Multi-Track Grouping > Group Tracks in Folders (or Group All)

Ah, ok thanks. I'll try that next time. I just did it independently soloing and lining the edits up.

Oh, this would be so useful. I wanted to record guitar both through mic and the cable but was not sure how edit that later.

As an alternative method, I would record the two signals as the left & right of a stereo track. After selecting and combining the best takes, split the resulting stereo track into 2 mono tracks.

Kev999
As an alternative method, I would record the two signals as the left & right of a stereo track. After selecting and combining the best takes, split the resulting stereo track into 2 mono tracks.

This is creative one too. But if one signal is direct and another is mic'ed how would you solve phasing issues?

You can also group them after you record if you forgot to check the grouping while recording. Just open all the tracks take lanes.  In the top track select the first clip and then scroll to the next track and hold "ctrl" (I think or it may be shift) while clicking on the corresponding clip in the next track etc.  Once all the corresponding clips are selected right click on one of them and select "add to selection group" (or something like that). Do that for all the takes and now you can edit them together.

Thanks for the suggestions. It's too late for this project but I'll try them next time.

Afrodrum

Kev999
As an alternative method, I would record the two signals as the left & right of a stereo track. After selecting and combining the best takes, split the resulting stereo track into 2 mono tracks.

...But if one signal is direct and another is mic'ed how would you solve phasing issues?

 
If there are phasing issues, whichever method you use to combine the signals won't make any difference. Maybe after finally splitting the signal, shifting one of them slightly along the timeline would help. But anyway that's a different topic.