Anecdotal data from gold wingers on a different site:
-Navy helo guy (no military fixed-wing besides training) just got an interview with Allegiant at 400hrs (SIC) at PSA.
-Cobra guy hit 1,000 hours 121 sic got hired by Delta (but had 3600 hrs AH-1)
-Another Navy helo bubba, started with SkyWest Feb18. Job offer with Atlas 747 in December. He's at 650 hrs ME part 121, nearing 1000 TT FW.
Do you know what you're getting into with CBP? I flew with them out of NASNI once and worked with them on Counter Narcotics missions, so I picked their brain quite a bit. First of all, it's shift work. You get assigned to an 8 hour shift. You have to be there for the entire shift whether you're flying or not. You don't have a ground job if you don't want one, but...get used to watching youtube videos to pass the time. You can fly both fixed- and rotary-wing which is awesome. Day-to-day, you might go out for a 3-4 hour bag, but a lot of it will be burning time. I flew in their King Air, we got up to altitude, flew down the coast of Mexico, boxed it off, and went north to shoot an approach at SBA, then went home. They had a sensor operator in the back who was a retired USCG Rescue Swimmer. We bullshitted the entire flight while he looked at random contacts.
You don't have much choice in your initial assignment location. Get ready to live in East Texas or Puerto Rico, those are their normal initial assignments (I personally wouldn't mind the latter, but that's me). The organization is flooded with Army types and they do a lot of things the Army way. Have fun with that. If you end up on the Customs side, know that they are only legally permitted to interdict in our TTWs. That's a huge limitation. Huge. If you actually want to make busts, you're better off at HITRON with the USCG or possibly HSM-60 on the Reserve side (not sure how much action they're getting lately).
On the other hand, you could suck it up at a Regional for a year or two, supplement your income with the Reserves, and then buy your own helo once you're making real money at the majors. Just an idea.