All I do is copy the files from the MPEG folder of the SVCD, then rename them as part one and part two. MPEG2VCR can handle it, or the merge in TMPGEnc. Just load part one, use edit to find out where it ends. Load part two, use edit to have it start right where part one ends.
If you have 2 SVCDs, you should end up with a file that is at most 1.6 GB. Some DVD players can handle SVCD MPEG2 files, some cannot. What I usually do is load the merged file into TMPGEnc and convert it to Half-D1 using the KVCD template. This way, I was able to fit two movies 3.2 GB on one DVD.
My next project is three old Universal Horror pictures, Frankenstein, Bride Of Frankenstein and Son Of Frankenstein, all three should fit as Half-D1 files.
For another solution, try this guide:
http://www.dvdrhelp.com/forum/userguides/159399.php