Is it best to have one strip of amp and pedalboard settings, one strip of vocal settings and one Suitcase Playback song file, OR one amp, one vox and 10 Suitcase strips accessing each Playback song?
Huh? What is a 'Suitcase strip', this sounds like the instrument strip of Mainstage which has the Suitcase instrument loaded by default. If you see always 'Suitcase' you should give your channelstrips meaningful names.
However, if you mean that you have 10 different playbacks, aka 10 songs, then you want 10 patches. Why? You want to start the playbacks somehow and a comfortable way to start a playback is to select the appropriate patch and let the playback run automatically. If this is not what you want, you can start it on demand. In the most simple setup, you have one playback per patch.
For your guitar and vocals it depends if they have always the same settings or if the settings depend on the song.
Let us look at the structure of Mainstage:
As hierarchical levels we have
Concert, Sets and
Patches. The highest level is the
Concert. What you add here, shows up in any
Set and any
Patch. The next level is the
Set. What you add here, shows up in each
Patch that resides in this
Set. The Patch itself is the lowest level. See it like a folder hierarchy. Concert and Set are containers, Patches can be played:
Concert
- Set A
-- Patch 1
-- Patch 2
-- Patch 3
- Set B
-- Patch 4
-- Patch 5
- Set C
-- Patch 6
-- Patch 7
-- Patch 8
and so on.
It is a matter of organization. Same settings for guitar and vox throughout the whole gig? Put those on concert level and they are available in all sets and all patches. If there is nothing else than playback, each patch (=song) would only have one individual channelstrip with a playback plugin.
Always the same guitar and vox settings but you don't want them on concert level? Create a set with your two channelstrips and put all patches (songs) into this set. Then your guitar and vox settings appear in all patches within this set.
Different guitar and vox settings for each song? You have to create channelstrips in each patch (= song) individually, to adjust them individually.
Different guitar and vox settings within a song, for example intro, verse, chorus solo etc? Create a set per song and put all the parts as patches into this set. Then a set represents a song and the patches are sounds for the parts. In this case the playback runs on set level and you can change the sound for the individual song parts while the playback runs.
Always the same vocal settings but different guitar for each song? Put the vocals on concert level and individual guitar strips in each patch.
I think you got the system.
There are two basic ways for sharing resources like reverb, delay, compressor etc. One is the bus, that can sit on either of the three levels. The second is the Alias. You can copy a channelstrip and paste it as alias wherever you need it.
I hope this was clear, if not don't hesitate do ask for a better explanation.
Btw, you should read, practice and understand the chapter #8 of the Mainstage manual "Playing Back Audio in MainStage". Actually this single chapter tells you almost everything about the Mainstage hierarchical system what I told you above.
I could just show you the well-known sign ...
... but this is not our style here. So you haven't seen it, ok?
... it requires a certain amount of fiddling on the laptop keyboard for selecting a Playback song
From the English Mainstage Manual, page 128, "Using the Playback Plugin":
You start playback by sending a Play command to the Playback plug-in using a screen control, such as a button, mapped to the Play/Stop parameter of the plug-in. To stop playback, you send a Stop command using the same parameter. Alternatively, you can set the plug-in to start when you select the patch or set, or when the Play action is triggered.
This is usually done with a controller. You sound as if you were not familiar with Mainstage screen controls and hardware controllers. Don't you have a controller? Such a device is essential for Mainstage. As you said, you want to seek contact to the audience and not show them a busy operator at work. Changing a patch or starting a playback can be almost unvisible to people, a tiny movement of your foot or hand if your controller is set up in an economical way.