Go to lemon curd recipe - ratios, yolks or whole eggs

I just “gleaned” a bunch of lemons and would like to make a batch or two of curd ( and panna cotta, and preserved lemons). I found a recipe that says including a whole yolk makes it thicker,

which is better for everyone, since I won’t start an “What would you do with a dozen egg whites?” thread, but wondering if there’s a downside. Also wondering about the pros andcons of freezing it.