I've been looking at mudguards for a Macina Cross 10 Plus, although you are one ahead of me in that you actually have your bike! Interesting the frame doesn't have a hole for the bolt fitting the rear guard...
Anyway the hybrid mudguards I've found are the following (for the same 42mm Marathon Mondial tyres you have):
- SKS Velo 47 Trekking (I think these are the ones used on the KTM Macina Sport 10 Plus although they have to be modified as the seat tube is further away from the wheel - doesn't look great having the front flapping around)
- SKS Velo 55 Cross
- SKS Beavertail, or even Beavertail XL although they might be too wide
- The Zefals you have tried
- Zefal Swan 45mm wide (rear only, but they do similar fronts). Doesn't provide much protection for the rest of the bike though.
For my own use (commuting) I've wondered if it might be better to go with some full mudguards. In particular the
SKS Bluemels Matt would go with the matt black of the bike and I think the 45mm version would work well.
Michael