Ah the joys and negative perks of “moving up” in the CFI world... You are learning that “moving up” means more $$ but less hours... Remeber this 30 years from now. Why not stay with your same 141 gig and go back to primary instruction? If your goal is 1500 hours ASAP, that’s what I would consider doing if I were in your shoes. 135 SIC is hit or miss on rapid accrual of flight time.