Lots of good discussion here.
As far as the manufacturer recommended matches, let me add this from Direct Connection.
With the Accel 150001 Coil, there is only combination listed.
ECU: Chrome (p4120889, P4007298, p4120505, p4120534)
Resistance value: 0.8 Ohms
All applications to 6000 rpm
From this, assuming your Chrome box is one of these or similar, I'd say .75 is a good match
This is taken from Figure 19-6 page 368 of Mopar Engine, Speed Secrets
edition. This version is terribly edited but I think my interpretation of the chart is correct. It may have been printed earlier as a Direct Connection "Chrysler Ignition Systems" bulletin.
Interesting. None of the combinations recommended in that table use a higher resistance.