I've created a new tool for calculating break chances. It is a Google spreadsheet available at https://goo.gl/3Ixnr7.
The main difference between it and BobTheBuilder's tool (http://sh.tstr.no/index.php) is that it gives the calculated break chance per item. Instead of making sure no items break, my goal is to allow a certain chance of some items breaking, as long as they aren't the expensive items. This tool gives the probability for each individual item to break, helping to guarantee that the most important items are safe.
As a further aid, the tool adds up the expected value of broken items, so you can see the total cost of going on a mission for different configurations.
In addition, I hope that the spreadsheet format will be more convenient to use.
How to use:
1. It is recommended to start by making your own copy of the document (File -> Make a Copy). This will allow you to put in your own numbers without interference from others.
2. The document has several sheets, the most important one is the first, titled "Main". Most of the rest are just internal calculations.
3. There are 6 sections, one for each hero in the team. You can specify for each hero their support, resourceful, supplier and fastidious. (See Bob's guide for an explanation of what these all mean.
4. Each section has 7 rows, one for each item for the hero. For each item you can fill in the following:
a. Item Name - Optional, allows you to identify which item is which.
b. Value - Semi-optional, the cost of the item. This goes into the calculation of the total mission cost. You can use any unit you want - gold, gems, whatever, as long as it's the same for all items.
c. Break chance - the base break chance of the item, which you can see on the hero screen.
5. In the Final chance column, you can see the actual probability that the item will be broken, taking all skills into account.
6. Under "Total Mission Cost", you can see the total of Value * Final chance for all items, which is the expected cost of replacing the items that will be broken during the quest. You want to keep this low, by making sure that the high value items have a low final chance.
7. On the right, you can see the distribution of the total number of broken items. This is equivalent to the data available in Bob's tool.
8. The "Data" sheet is the place to store different configurations, either for different teams or various possible setups for a specific team. Copy-Paste between the two sheets as needed.
In an ideal world, values would be updated instantly once you change the data. However, the tool involves some fairly heavy calculations, and Google Docs isn't too fast, so you may have to wait a few seconds for the update.
Since I don't have access to Shop Heroes' source code, I had to rely on Bob's information and make a few assumptions about how breaking works. Here are a few of them:
1. Supplier and Fastidious are all stacked linearly.
2. Support and Resourceful prioritize items with lower break chance. I am assuming the relevant value is the break chance after supplier and fastidious have been applied. There is a real chance I'm wrong here and priority is based on the displayed value before supplier/fastidious, if anyone has further info let me know and I can change that,
3. If items are tied for break chance, the leftmost items get priority, going through the heroes first to last, and then slots first to last. In other words, the topmost items in the list on the chart get priority. This is why you can have items with the same base break chance but different final chance - the topmost items have a higher chance to be saved.
There's always a chance I have a bug somewhere, though I did conduct multiple tests, both independent ones as well as comparing against Bob's results.
I know that releasing this tool in the midst of a 0% break event is not ideal, but I didn't want to wait unnecessarily once I was finished, and this tool will help you keep your break chances low even after the event ends.