you can leave optional third party tool software blank. its just a way to specify a program that you might want to launch easily to also work with programs running on your computer, like:http://www.sysintern...ProcessExplorer.html
as for ignore.. i think the only program i have on my ignore list is my cd burning utility, just so that process tamer doesnt reduce it. but a good rule of thumb is don't worry about it. process tamer will tell you when its taming a process, so if you find that it tames some process too much then you can add it to ignore list. even cd burner on a fast computer will probably not need to be ignored. the only time you really need to ignore things is if you have processed that use up 100% of your cpu that you WANT to be using up so much of your cpu; most people probably don't have such apps.
default settings: the only reason to change them is if you notice that process tamer is jumping the gun and taming an app prematurely, or not responding fast enough. an example: lets say you have a big program like photoshop which takes up all your cpu for 60 seconds while it is loading. and process tamer kicks in right at the end and tames it, only to untame it 30 seconds later. well that's kind of silly. in that case you might want to ignore photoshop, or adjust the settings to have process tamer react faster or slower.