Terminator has voiced a concern I often get. How do I handle the DS play.1st let me state that I began playing DS about 40years ago. The casino introduced the concept of inside and outside numbers. With different, and less favourable, rules for the outside numbers. It was aimed at curtailing system play. Which concentrated on outside numbers.
I studied the layout and wheel and decided that DS's looked like the best alternative. I soon four d that DS were much more versatile. I have not bet an outside number since, and will never do so again !!
How are DS better ? CHOICE ! In the case of dozens I have12 possible dozens instead of 3. With EC's 8 have 20 possibilities instead of 6.
How is this better ? Many years ago I embarked on research to find the best arrangements of bets around he wheel. EC's alternate, which looked lime a good arrangement. At no time would you miss by more than 1 pocket. Yet I found that 3DS usually performed better. I won't bore you with the painstaking research that followed. Even if I HD the skills. Computers weren't available.
Mi found wheel sectors were more reliable. Divide the wheel into halves, thirds, quarters, or sixths, ninths or twelves and the results were likely to be better than EC's, dozens, 3 streets, DS, quads or streets. Tohe problem was tracking and betting these sectors was laborious. There had to be an easier way on the layout. So I judged the DS until the results showed a consistent improvement.
So I don't bet dozens(DS 12,34,56) I bet DS pairs that include 1low DS and 1high DS. That gives me dozens(12numbers)that include an equal number of R.B.O.E. and H.L. I then loomed at the pattern of bets around the wheel. Alternating groups of 1 or 2 wasn't the answer. That was featured on the 2 wheels. If it were bad for them the casinos would have changed it. I found that a group of 4 and 3 with a minimum of single numbers spread randomly around the wheel gave best results. That is the reasoning behind my DS play. It is highly likely that similar results would work for for other bets. You will have to do thàt research yourself.
So for an EC bet I use 3 DS. For dozens I use 2.
Terminator you got the betting right. The 2 extra safety (insured) bets seem to pay their way.