I think it would be a big mistake to get away from the fresh oysters in the shells Mr. Slick. You developed a love for this style of cooking them and it is clear you have worked really hard to keep true to what you enjoyed. That picture above would not look the same if it were in some tin boat. I am sure that those who ate with you also appreciated the work you put into it – it helps create a overall experience. I say work through the issue.
I am sure that you have problems because you don’t work with them enough. Growing up on the coast I have eaten oysters many ways and raw is still my favorite. I suggest you find a strong flat tool and practice going in the oyster slightly above the hinge and slide back to help pop it open. You can put the oyster on a towel and fold it over the top to protect your hands and keep it from slipping.
Also the point about oysters in months with “r”. It is not a temperature thing as much as it is an issue about salinity. Too much fresh water introduced rapidly into the oyster beds from rain water and run off allows for bacteria to develop. This affects the taste and in some cases the safety – red tide issues. If you look at the months with “r” it normally falls during the time of seasonal weather change. Today they have developed many ways to raise oysters where they can control the fresh water coming into the oyster bed and some beds are far enough out that they are not affected by it.
Good luck with your cook Mr. Slick – I am sure whatever you decide it will turn out great.