Sorry I didn't see this earlier.
There are schematics for the RV1 1433 and 1419 in Rick Astley's very good book, "MGB Electrical Systems: The Essential Manual." Much of the info in this book is relevant to Spridgets, MGAs, and so on--no great surprise. A little hard to obtain; I think I got mine from Amazon, but I had to wait a while for it.
I left a copy of the 1433 schematic in the other thread. Anyone wants the schematic for the 1419, let me know and I'll scan it too.