Ok, so i dont know about bloods or short tails specifically, however, i do know some about costs, genetics, and basic business principles.
For costs, youll need to look at how large scale are you going, and the quality of starter animals you are looking to get. If you buy cheap animals, expect low quality, this isnt a definite, but usually, you get what you pay for, the better looking the animal you produce, the easier itll be to sell. So figure out number and quality you want to start with and add up those costs.
Next, anticipate buying storage for all of your adults, depending on the number this could be hundreds, or this could be thousands. I have 28 snakes (carpets and balls) and my housing for them cost around 20k in enclosure costs, enrichment, substrate, etc.
Now, figure out electricity costs and food costs for the number of snakes / enclosures you will have. For me, its about 200-250$ a month for heating my tanks and about 100-150$ a month for food.
Again, do the math for your number, not mine, mine is just an example based on my 28 snakes, if you start with 4 (1 male, 3 females) then your costs wont be the same as mine. If you can accept these costs, then start looking nearby for exotic Vets, at some point you will likely need one, and knowing where they are and building a rapport with them will help you in the long run.
Now, research the animals, what care do they need, what is their clutch size, can you provide what they need, and can you handle the amount of young they will be putting out? If the answer is yes, now you need to factor in costs for storing the young until you are able to sell them, the cost of buying or making an incubator, and develop your plan for time management for taking care of the eggs.
Now its time for market research, what are the expected sell prices, what is the market saturation, what morphs sell well, and which ones sit around a long time. What morphs do you enjoy and would like to work with. Figure this out and now you are ready to put all the information together and do a cost analysis.
At this point you need to start saving up money, or plan to take out a loan to get you started, and unless you buy adults, plan for no income from this for the first 3 years, but you will still have expenses via electric, vet costs, substrate, and food.
If you can handle all of this, then once you are ready, get all your equipment, get it all set up, then once everything is ready, get your first breeder snakes and start your journey :). Remember that as you breed your collection will likely grow with holdbacks as you try to increase quality, and that snakes you have at first, you may end up rehoming to maintain space for the next generation depending on how serious you get into this. Care for your animals but if you are doing it to produce better quality, i dont suggest becoming attached. Give them the best care you can and enjoy them while you have them