So as soon as the boat is finished, rigged, and on a trailer, the plan is to create videos of a couple different activities. Find a small lake to launch in, pull her over and show we can right her again. Then, on probably multiple occasions, sail on some bigger water in stronger winds testing the boundaries of what we can do.
The footage will be posted on this blog.
The Weekender design and Kingsfold's modifications in particular have some useful features in this context. I shared Team Kingsfold’s status on a forum dedicated to the Weekender design, commenting specifically on the permanent foam flotation I’ve added, and the compartments that are sealable, and that I widened my transom 4” beyond the stock design. I received these comments from Paul Riccelli, a yacht designer and expert on the Weekender, and Al Stead who built and actively sails a Weekender.
The capsize tests previously done will be a fair bit different than your build, though I'll bet you'll be a little disappointed about the results. My capsize screen of a stock Weekender shows a max of about 70 degrees of positive righting arm, usually less, because they tend to be built heavy. I'll bet you're a little better than stock, because of the raised cockpit sole and hopefully some side and under side deck flotation you've installed. It'll still suck, compared to other boats, but this is not your fault, but a function of a relatively narrow, flat bottom, short LWL craft. This is common of boats shaped like this, in fact, you're will be better than the average, short and flat bottom boat, but not ideal in the conditions you'll see.
[What you described] is about 140 pounds of flotation, with the foam (not much) and another 40 pounds in the keel, though not very handy in this location for these types of tests. With the seat backs sealed, the forward bulkhead sealed up, you'll approach what is desirable in a swamping, but roll over prevention is more a function of hull shape and CG location. The wider butt should help quite a bit too. ... I'll bet she holds up to a press longer than the stock transom, with softer heel angles, though if she's heeled over a fair bit, so the transom drags, steering in particular and handling in general, will likely get cranky so reef early. The wide transom will also make following seas dangerous, without careful skippering (she'll want to broach more readily).
... The biggest thing to keep you safe is to be able to seal up the cabin in bad weather. If that stays dry, you are good to go.
That gaff rig is your ally. ... You can spill tons of air in a split second as well as lower the center of effort. [The peak halyard will be routed to the cockpit and clearly marked so we can scandalize the main in a moment.] That low aspect rig will help you on most points of sail other than going to weather. ...
After sailing Duckie for eight years, I think that the Weekender is a pretty reliable little vessel. She is not a blue water boat, but she's not bad in a blunder.