On WL wiki, I'd be very happy to find full info about calculation, luck, luck modifier and a fair share of examples on a dedicated page. To be honest, Fizzer, the help page about luck may be too light, and doesn't help me thouroughly although I do maths and stochastics on a regular basis.

I use the "Analyze" button a lot lately (found on the pop-up when you attack a territory). It shows you what the success percentage is when you attack and you can adjust the number of defenders for different scenarios.

I think this is quite useful as I don't want to use a seperate calculator and it shows you with how many you should attack to get it 100% sure.

In addition you can also use it to see how many defenders you need to not lose the territory, but that is a bit more advanced maybe.

the problem with the analyze tool... is that instead of giving completely accurate percentages.. it runs the scenario a set amount of times and gives percentages based on the results.. you can see this when you view the analysis for the same thing multiple times.. to the point that sometimes attacking with X is a 100% win rate.. and other times attackign with X is a 99% win rate, while it recomendes X+1 for 100% win rate..
while this seems a minor problem, and for most needs it is unnoticeable.. if your that one oddball that happens to lose on a 100% chance, it'll seem like a pretty big deal..

Anyway, I don't mind using pure algebra and I'd like to have all tools I need to proceed this way ^^
By the way I never use the analyze tool. Maybe I should, but still, I find it just boring and I'd even strongly recommend having it away from the game, at least in rated games. Just like in, for say, poker, you don't have a calculator to tell you how far you are from winning : it would badly hurt the ability you have to ponder what depends on you and what not, and that may be precisely what makes it so thrilling (well I'm not a poker fan, but I guess it's a pretty convenient example).

Thanks for the hint at the Analyze tool. It is interesting to see the probabilities of success for attacking neutrals in a 75% luck game.

personally, I never use the analyze tool in actual games.. I generally forget it's there..