I don't see any tuning offsets/sweetners/presets (default or user-defined), similar to Peterson. The most common for standard electric guitars, designed to compensate for string deflection and the "sharpness" that occurs when pressing strings to the fretboard, are: E1 (High E): -2.3 cents
B2: 0.0 cents (or slightly flat in some iterations); G3: 0.0 cents; D4: -0.4 cents; A5: -2.1 cents; E6 (Low E): -2.3 cents.
If there's a way to do this with the Stadium built-in tuner (e.g. not with a Variax) please LMK, otherwise please add to the Line 6 suggestion box. Keep up the great work, Line 6! -b