If the 135 Gig can't guarantee you more than 500 hours per year find a good CFI gig that can. You do not need to spend the next two years fretting to ATP mins in a 300 hour a year job. Legacy retirements really start to go up in two years. You do not want to be stuck BEHIND the wave in a career where seniority is as important as it is in 121 flying. Especially when you would be entering at age 45.