Well, since the rim size is the same, and the only difference is the offset, then the difference is 7mm further out if you go with the 35mm offset. If you go with the 42mm offset, it will be the same as the Enkei's you already have...
You can go to this link and see what the difference is between your current one and the new one. This is good if you're going with different rim width's.
BTW, I run a 7.5" rim with a 42mm offset, and it's perfectly fine... I don't see a problem with going out 1mm more ;)