You understand it pretty well, but let me add some further thoughts.
Extreme-os is a stock system, and thus the trade sizes recommended by it can in fact be multiplied by almost any scaling factor you desire. Example: If the system usually trades 100 shares of stock, then a 50% scaling factor is perfectly fine: you’ll trade 50 shares.
But Bob Dylan is a futures system, and here things become a little trickier. You can’t really trade 50% of a futures contract. So, if you type in that you want a “Scaling” of 50%, and then the C2 Model trades 1 contract, you will trade:
50% x 1 contract = 0.5 contracts --> (C2 always rounds downward) == 0 contracts!
In other words, you will never trade.
So in general, with futures systems, you’ll want a multiple of 100% scaling, i.e. 100% scaling, or 200%, etc.
Now, if you look at the system’s track record, you’ll see that it consistently trades 1 contract at a time (sometimes 2). Since the initial margin of the @ES is approx $6,000, you should be able to handle two contracts, even if the system holds them overnight.
However, if you feel uncomfortable about the possibility of trading two contracts, you can do the following:
Set Scaling = 100%
Set Max-Contracts = 1
In this case, you will always trade one contract. In those rare cases where the Model account trades 2, your “max” setting will prevent the second contract from opening.
Of course, my entire answer is caveated by the following: I don’t have any idea what your risk preference is, and you need to make all trading decisions independently. I’m merely trying to explain how the technology can be made to work under the parameters you described. Remember that you can lose all your money trading.
On that cheery note, good luck! 
