Whichever direction you decide to go, private or working for a firm, my 2 cents would be to continue trading the same contract you have been for years. That alone is a huge advantage. Perhaps you were scalping off of order flow, hence your trepidation regarding screen trading. However, each market has own tendencies, it's routines, it's ranges, and your already familiar with that. Now all you need to do is develop a strategy to capitalize on it.