That plug was designed to reduce lead fouling over the 40 version. I think you will find that any of the auto plug are far more resistant to lead fouling than the 37BY.
I have one SDS CPI ignition and one Bendix S-1200 on my RV-10. It runs BR8ES plugs on both ignition systems.
I modified the mag cap using the instructions from G3 ignition. The task is relatively easy and it has been working flawlessly for me now for about 500 hours.
I got the spark plug adapters from Ross at SDS.
My Glastar used RRM37BY plugs in the O-360. I replaced them with NGK BR8ES plugs when I changed the ignition configuration to P-mag and one 4370 slick.
The plugs for the EI and the mag will need to be gapped differently. I think mine are gapped .034 and .018 respectively