These are theoretical, simpler tunings/arrangements for setups with fewer than 10 strings / 5 individual tones. Each tuning has only one change per string, and they only sharpen. The notes I chose are only for reference with each other since scale length and gauge will determine the actual notes used.

This is a pair of raise-only setups separated by a third, and each provide slightly different ways of playing the same-ish base chords. I've paired them together since swapping between the two would be quite simple, with a 3 st key difference instead of 4 since it’d take 6 tuning adjustments instead of 8 to change between tunings and the static note would remain the same. Either way, Fm/Ab would work just as well since all tuning changes would only be half step increments.

Major open (C & Am)

	R	S	P
E		F +1st (3^4 / 5^6)
C			D +2 (1^2 / 3^4)
B
G	A +2 (5^6 / 7^1)
E		F +1st (3^4 / 5^6)
C			D +2 (1^2 / 3^4)
B
G	A +2 (5^6 / 7^1)

	open	R	S	P	RS	SP	RP*	RSP
C w/o B	I	vi	Is		IV		vis	ii
C w B	iii			iii		V7		viiø

Am w/o B	III	i	IIIs		VI		is	iv
Am w B	v			v		VII7		iiø

Mediant open (A & F#m)

	T	R	S
E		F# +2st (5^6 / 7^1)
C#			D +1st (3^4 / 5^6)
B
G#	A +1st (7^1 / 2^3)
E		F# +2st (5^6 / 7^1)
C#			D +1st (3^4 / 5^6)
B
G#	A +1st (7^1 / 2^3)

	open	T	R	S	TR	RS	TS*	TRS
A w/o B	iii	I	iiis		vi		Is	IV
A w B				V7		viiø		ii

F#m w/o B	v	III	vs		i		IIIs	VI
F#m w B				VII7		iiø		iv

*impossible in a 3 pedal configuration paired with a volume pedal. Ideally, the setup should have at least one knee lever.

Examples*

2-1-2 tuning

I - IV - iii - V7 in D. Tab

*Simulated digitally. Ableton preset if you want it, it's only convincing when used for similar chord motions otherwise it obviously just sounds like a woodwind