Thanks for all the replies.
I fully understand what the restrictor does, and if I had steam gauges I fully understand why it is necessary, but with P-mags and the ACS I doubt it is, since it is trivially easy to smooth in the software which lies between the instantaneous reading, and what is represented on the screen. I would have thought Dynon would do this but someone said 'no'. Thanks.
Anyway, that aside I realised I did in fact have one of the VANS oil/fuel restrictors left over, and since I had to dissassemble the manifold that all the hoses arrive at, on which the transducers are mounted, I put it into the end of the line from the engine manifold. The reason I did this is because I am concerned just how lean the engine would run on that cylinder if something ruptured, so it is the engine I consider I am protecting.
N941WR asked where to install it.
If you want to take a look at the third picture down (double click it to enlarge), it is at the end of the black hose coming from the primer port on #3. (In fact if you have the VANS manifold pressure kit I think they provided a part with a restrictor.) In the picture the nearest position on the manifold is the oil pressure, the middle the fuel pressure and the furthest the engine manifold pressure, so you cant actually see the relevent connector. But it is the same as the nearest, just a 45 deg black steel connector with a restrictor but otherwise like the blue one in the foreground. This is a -4 so the transducers are in an unusual place. yours are/will be probably on the firewall.
How to make one I will leave to others who have done it. I happened to have one.
Thanks for all the inpus. Cheers!