At least 500 TPIC at this point. With the retirement wave probably peaking and ramping down, 1000 might be a safer number since that's historically been the gold standard. Might not want to go to a ULCC and then get stuck if the competitive TPIC goalposts move soon after (that might happen with age 67).
Also I'd only prioritize SW or AS if you live in a base where they are the only option. If Big 3 are a practical option, do that. More retirements, different airplanes... 38 years is a loooong time to fly the 'ol guppster. Although if the HA merger goes through, AS will have at least one WB fleet.