Legal minimum for air taxi work (single pilot ops) 700tt with 40 p1 multi.
Realistic minimum 1000 hours tt, with 200 p1 multi.
Someone who has flown an automated multi crew jet for the last five years will not be a suitable candidate for single pilot Air Taxi work in a piston twin. So the ex-airline bods will in general not be in the running for Air Taxi work. The trouble at the moment is no one is moving up the chain to free up vacancies in the Air Taxi companies. Revalidated my FI rating last summer and still haven't found any part time instructing work.