"SPICA is adjusted correctly and by the book, with the likely exception of the fuel/air mixture via the cold start solenoid which I can't seem to get right." The "running" mixture is adjusted via the fuel shut-off solenoid, not the cold start solenoid. The cold start solenoid is adjustable, but only effects the enrichment when cranking. Sometimes the cold start plunger can get stuck and cause way rich mixture. A quick way to test cold start solenoid adjustment is to energize it while the engine is at FOT at about a 900rpm idle. When energized, it should drop idle speed, but not stall engine immediately. Burbling on decel can be caused by a faulty micro switch, maladjusted short or long rods, or inoperative fuel shut-off solenoid. Easy test for micro switch operation with a test light. Remove fuel shut-off solenoid and energize to test. Several threads here on adjusting the fuel mixture at the fsos. I just lean em out until they wont rev-up or run, then slowly add more fuel. Then do plug checks. If the car wasn't run for years, have you checked for rusty tank, clogged fuel filter, fuel pressure?