I can't speak to your wire size, but in the worst case, just make up some convenient short leads in 1AWG. Run them a foot or three over to a nice solid bulkhead and install a junction box. Then run the heavy cables
aft from the junction box.
The junction box might be a good place to install an extra cut-off switch, etc. if you have any need for that as well. And at some point, if you should decide to install a windlass battery
forward, that could be the tie-in point for it as well.