For Charter flights as mentioned in the original post.......
I have a interesting proposition - (have used it myself - Sorry RSA)
Have your company not only give you permission to perform the flight making them take into account your flight and duty time requirements - but have them bill the company requesting the flight with any money going back into your company to ensure you are in fact doing the flight due to your "Passion for Aviation"
I remember when a "Moonlighter" I know missed his flight and delayed his airlines departure due to a technical problem with his "Moonbuggy"
