I don't think the "surf" rating should weigh so heavily on your choice unless you intend to paddling in some scary conditions. I've paddled a short, wide, extremely stable kayak in rough water (well, 2-3' steep chop - "rough water" is a relative term) and it handled fine despite the fact that many will say that its not meant for such conditions (and certainly it doesn't excel in those conditions, but it was definitely manageable). I make a point not to take it out in conditions that are above my paddling skills, but obviously on a long trip and/or in certain locations you may not be able to avoid difficult conditions.

As for your building time frame, have you thought about a skin on frame kayak? I think that might be much more feasible for a 4-week build (especially a "Yost" style wood frame). You can add hatches or use dry bags/combination float and dry bags inserted through the cockpit for storage instead of hatches. A skin on frame need not be a low-volume Greenland boat made for rolling only, there are various designs on the 'net that should be comparable to "expedition" strip-built/stitch-and-glue/fiberglass designs.

Stitch and glue might be a another good option if you desire a wood and fiberglass kayak in 4 weeks.

Good luck whatever you choose to build!