First of all I'd try both the feet and pads as these are easy to fit and they might be enough.
To make the wedges I'd cut an oblong block of material to size, drill the vertical hole for the bolt, then cut it in two at the required angle, giving you both wedges. You might need a longer bolt.
The tricky parts for me would choice of material and getting the diagonal cut right. Wood would be easy to work but liable to split, metal strong but hard work, so a suitable plastic would probably be my choice.
I do appreciate that these things that sound easy are much more difficult without some sort of workspace and tools