Are your cats Pkdefic tested first of all?
http://bit.ly/zhsMMw very important to do if they aren't.
Mouth Swab test, easy done, cheap and will tell you whether it is safe to breed from the cats you have.
HCM testing, important too, HCM common in the breed. Pedigree is important, make sure you know the main HCM cats as each HCM cat has a 50% chance of producing HCM in their offspring, a pedigree full of HCM will mean a cat has a very high chance of having HCM too, no matter how many "negative" young cats there are.
Then you need to look at pattern re your first question.
Rosetting is basically a recessive, so can be visible (homozygous) or can be carried(heterozygous).
If you have cats that are out of non rosetted parents with ancestors that were also non rosetted you need to introduce rosetting into the line. Even if you do that, you may still get non rosetted cats but all kittens of that mating will be carriers.
Most Bengal cats have the classic tabby pattern, the spotted gene breaks that up to produce spots and the "rosetted" gene on top of that produces rosettes. On top of all that you get polygenes who finish the process, so you either get huge pancake rosettes, arrow heads, small rosettes, clarity, colour, etc etc. It is all about selecting what you want to achieve and discarding cats that do not make the grade.
In order to produce the best you have to have a strict cull policy, removing unhealthy cats and cats that do not "produce", ie infertile, endometriosis, poor mothering, no milk, difficult to get pregnant, poor quality kittens, sickly kittens, bad temperament either in themselves or in their offspring, poor conformation etc. etc. It is amazing how often these traits are passed on.
Although it can happen that you get a fantastic kitten from poor quality parents, the "depth of breeding" just isn't there, and often these freaks of nature do not pass on their stunning looks to their offspring.
If you want to be a good breeder, then sentiment just doesn't exist. There is no point in producing poor quality kittens to flood the market. So Bertha with her sickly kittens or her poor conformation or her dodgy temperament needs to be neutered, not given x number of chances which will all just pass on the same dodgy genes.
Breeding well is not for everyone, but unless you have realistic goals to produce really good healthy stunning cats then all you will be doing is adding to the cat and kitten crisis, in which perfectly healthy animals get put down every day.
Personally I wouldn't have started with a lot of cats, Bengals are not the easiest breed to breed, they have many problems. They are "fast" too, in that cats go out of date really quickly and what is good today may be old hat tomorrow.