This may be a dumb question but here goes

I bought a new Terrova 80lb 24v and am excited to install it this weekend. The TM I am replacing on my boat is an old 12/24 4 wire system that came with my Lowe 170. It's a 1996 model boat. I was getting ready to replace the old wiring (I believe it is 10 gauge) with the 6 gauge that Minn Kota recommends and had the idea of just using the old wiring and splicing the negative and positive cables together to make the load more suitable for the Terrova. In other words, using 4 10 gauge cables instead of 2 6 gauge. Would that work or am I crazy? Like I said, My plan all along was to change it out for the 6 gauge wire but I would love to avoid that if possible because it looks like it's going to be a real hassle in this boat. As you can tell, I am pretty clueless when it comes to wiring. I just love fishing. :D