I am trying to mesh lines of different sizes, but i want the nodes to be spaced exactly the same for each line. I am using Gambit. I have been able to do something using the first length grading scheme, but as it goes out further, the points start differing form each other.

I would split the longer line of the two with a vertex to get two subedges. Do it in such way that one subedge is exactly as long as the other line that you have. Now you can mesh that subedge and the line with the exact same edge intervals.