Hi pals and guitar lovers 
Waiting that Scaler devs find a way to have Keys-Lock optimized for the guitar, I found a wonderful and easy workaround for AAS Strum-GS 2 in Guitar mode (without Auto)
Here is the routing: 2 identical instances of Scaler each driving a guitar with different amps
Broomstick Bass with its drummy metronome gives the groove needed to play properly the accompaniment & the solo
Here is the XML, identical for the 2 Scaler instances: no Keys-Lock selected, and no Performance
Just the series of chords in Section C
Scaler state (17.9 KB)
And here is the trick
1 step - In the 1st guitar track I record the accompaniment hitting just the Strumming keys with red lines, i.e. Upstroke, Palm mute, Downstroke, Muffled down, and Muffled up
With a little practice even a poor guitarist like me is able to produce interesting strummings, and with many variations
2 step - In the second guitar track I record the solo hitting just the Arpeggio keys from Arpeggio 1 to Arpeggio 6
The 2 Scaler instances have the same series of chord and are in sync, so the solo arpeggios are perfectly tuned with chords! 
There is one issue only: at the passage from a chord to another, the guitar sound ceases suddenly, and I think to remember this is a Scaler’s bug that will be possibly fixed in the next release, but I found that using the keyboard sustain-footswitch properly I can fill the gaps
Have fun and let me know what do you think about