Def have someone go over your cover letter and resume. Worth paying a pro to do it. Look at Falcon 20 cargo operators like IFL, etc... local 135 outfits that are pax. They need people that will stick around. Prob 500ish hrs a year out of a pax 135 jet operation. 300 is low get some multi time prob a min between 25-50. The higher the better.
EDIT: You're building time in FL. Look at 135s out of FLL and other local airports. They tend to hire lower time FOs