It may be worth a few enquiries direct to potential employers to test the water; they should give you a reasonably honest assessment of your potential.
Be warned though, if you give up the day job entirely and rely for your livelihood on the charter level of the rotary world you will face a great deal more ****ing about than in the airline world; I don't need to warn you about the income expectations. It can, however, be genuinely interesting and varied stuff. Feel free to email me if you want to talk in depth.