changing hp requirement of an implement

[DirectCedar]

I want to change a couple mod implements to make them harder to pull in the vein of the MR mod (which is just awesome btw).

I've found the required hp variable in one location in the xml file for the mod I'm working on. Is it just a matter of increasing this number, or is this just what appears in the shop description and are there other variables in this xml or in any other of the mod's files where I need to adjust something to change the hp requirement? Do I need Giants Editor to change something in an i3d or can I make the changes just in .xml's using WordPad?

Yes I know I could figure this out by trial and error but I thought I would just check first if someone has done it recently and could save me some time (and a lot of mistakes)...

Thanks in advance.