Cut one of your substrates in half and put the extra seam where it won't be seen. 4'-8'-4'. Glue your substrate seams and sand everything flat before applying laminate.
Interesting to see how many use a table saw to cut laminate. Most of my laminate experience has been on a job site, cutting down a 5' x 12' piece of laminate with the only table saw in sight being a 8-1/4" Makita in a Rosseau(sp?) auxiliary table (and let me tell you, that was the cat's meow back in the day). Scoring is quick, easy, quiet and accurate. No, it doesn't leave perfectly clean edges but those get flush trimmed anyhow. I have cut laminate on a table saw but I wouldn't use a good blade for it. It's just dulls blades too quickly. And all those little shards flying everywhere were sharp. But, as I said earlier, the edges left from scoring are jagged and razor sharp.