Greyscale, thanks! That's what I was thinking too...
Diana, thanks! I agree. And I also thought of dainty Oxfords as an option...
Thank you, Gaylene! It's already on its way.
Tulle, thanks! Yes, I would wear my taupe Oxfords with it. I don't have any other shoes that would be suitable. I do have some brands that have a much bigger chance of success, but you have to look hard for the right styles. Most sandal styles at the moment have fixed straps anyway, but even if they had buckles extra holes wouldn't help much - I don't need more volume on top but more width in the soles (especially in front). I've said that my Birks are just wide enough, but I have the straps in the second tightest settings (I think).