I don't find anything at all wrong with your collecting procedure, although I am not sure if collecting these corals is legal. Try E-mailing Dave at Gulf-View in Tampa as he is quite knowledgeable in this area.
As a collector of native Florida fishes I also come under fire from others who think that what I am doing is wrong but that is a different subject (dive into my rules and regulations on collecting native fish on my website if you want to know more).
The ornamental marine industry in itself contributes far more to reef destruction through the widespread (Indonesia and the Philippines) use of cyanide to bring fish to the surface for collecting. This is far worse than hobbyists who choose to collect small amounts of marine life for themselves. Most collectors like myself follow the rules and regulations and take considerable amount of care as not to disturb natural habitats. If you are not getting your SW fish from Australia, Hawaii, or another country with strict regulations on collecting, chances are you are contributing to the cause.
With this said, I would recommend the drip method (also mentioned on this website for acclimating). I would just make the drip a lot slower and do small amounts over several days to simulate a gradual change in a natural environment. I would also test the water chemistry from the areas you are collecting as I do.
Good luck with your frags!!