Which brake pads for these old cantilever brakes? I need to replace all the brake pads on these old Mafac cantilever brakes on my bike. I have currently a mix of the original style and a modern replacement. I went to a local bike shop and they gave me a modern equivalent of the original brake (pic below) but it doesn't fit because of the collar at the end of the stem. I could make them fit my adjusting the angle of the cantilever arm but I understood that they are supposed to be horizontal, as they are at the moment.
The modern ones I had on are worn down really unevenly, which I was wondering if this is poor adjustment or they just aren't compatible.
So before buying anything else, does anyone know if I could just replace all four pads with the modern ones (pic below).
Thank you!

UPDATE
I fitted the new brake pads to the rear brake today and they work fine (1st pic below). On the front they do not fit around the wheel (2nd pic). If there was no collar on the stem they would fit, and if I fit them with the collar past the holder they sit at an angle (3rd pic). Following all your advice I think I will loosen the cable first to see how far down the cantilever arms shift. If it is too far I will invest in a pair of very nice Kool Stop brakes. Thank you all!
I suspect that the splitting triangle is the only MAFAC bit that were often used for that purpose. The Mafac 'Racer' brakes are quite different, look them up in a search engine. I remember them well from my teenage years' Peugeot.
These look like traditional cantilever brakes formerly used by crossers and on early MTB. However it seems that there is a bit missing in the locking mechanism for the pads, some wedge- or hemi-spherically shaped washer(s) that allow for the adjustment of the pads' parallelism to the rims.
Could it also be that the pivots on the fork and rear triangle are wonky from an impact?