I just got the Bolide 25 (I think this is the smallest size in the 1923 style, the SA told me this is the mini size) and it's a really great size! It easily fits phone, small wallet/cardholder, and an SLG like LV mini pochette, but I also have a small folded reusable bag, pack of tissues, and could maybe fit in a small folded scarf. I think you also could get a pair of sunglasses in a soft case, for example, if they weren't huge. It fits more than the K25 because of the way it opens all the way, and because of its shape. I got it in noir Epsom and love that the leather feels more carefree and that it feels structured but not stiff. Absolutely perfect for dinner out but holds everything I need during the day too.
The strap is not adjustable, and is meant for shoulder carry (I'm 5 ft 2 in, and crossbody is doable but not ideal), but I just realized that one could get a longer strap as well since they clip on at the handles.
The style is classic enough for more formal occasions, but totally fine for daytime use too. This is really close to a perfect bag! (okay, no exterior pocket but that doesn't work with the style, and one can't have everything