If you can't tell which sound your are seeking of the complementary guitar, then you must decide by optical preferences: Hollowbody vs. Solidbody, bridge type (vintage, FR, Bigsby, fixed (TOM, stoptail; stoptail only, string through), body type single cut vs. double cut, pickup layout (SSS, SSH, HSH, HH, NF etc.), 22 vs. 24 frets, new vs. used.
Your S2 and SilSky are both double cuts, one with HH, the other with SSS layout. Is soundwise then something missed?
Maybe an 594 could be - due to other scale be an opportunity to go for.
Personally I decided once for a core model, which could have been the best of all worlds (if an piezo bridge would have been added). Nevertheless w/o piezo it's my best of most of all worlds with its given sounds by SSS, P90SP90* (or mini-HSmini-H)*, HSH voicings (in total 13).
A PRS 513.
Discontiued to the advantage of the 509, which is not a 513 w/o the heavy humbucking voicing. 509's humbuckers are vintage voiced only.
Talking about a new guitar, then I would go for the Fiore.
Or you could go in a total different direction with the NF53 or Myles Kennedy signature (both fixed bridges, both single cuts).
*comparable sound