Hey Mate,
I started a thread on Ford WSS-M2C913-D here
https://bobistheoilguy.com/forums/ubbthreads.php/topics/4543378/1
The 913-D is the updated version of the 913-C, and its based on the Euro ACEA A5/B5 spec, it is a 5W30 and it appears to have a decent high TBN and Zinc levels. The A5/B5 is very good spec., effectively full synthetic, and a lower HTHS oil ( below 3.5 cP) and is at the thinner end of the 30 grade.
Castrol Edge 5W30 A3/B4 is a full synthetic Euro ACEA A3/B4 oil with high TBN and Zinc levels. It's also a very good oil with a higher HTHS (above 3.5 cP) and is at the thicker end of the 30 grade.
I would have no problems going down the Edge 5W30 A3/B4 path, it seems to offer everything Ford requires but in a thicker 5W30 package. In theory you may use a little more fuel in laboratory tests, but it's unlikely your will notice any change in real world driving. Also in theory, the thicker oil will offer a slightly high safety margin for wear if racing, but it's unlikely you will notice any change in real world driving.
In Australia, it's often easier to find Edge 5W30 A3/B4 at a good price than it is to find a Ford 913-C/D oil at a good price, so it make sense to me what you are doing.
As an aside, these Ford 913-C/D oils are very well formulated oils, and they are the world spec for Ford. Yet the only place that doesn't use them is North America, the home of Ford. I believe it is because they are high in zinc (ZDDP) and as such break the API SN chemical limits (for Phos / Zn) and therefore must be classed as an API SL oil, no matter how good they are. The Edge A3/B4 is the same, its API SL, due to elevated Zinc / Phos levels, even though it meets all the quality requirements of API SN and even the very tough OEMs of MB 229.5 and BMW LL-01. It seems to me certain markets find it difficult to accept a non-SN oil, but those are not the Australian or European markets.