How did you get on with the DB37?
Like you i had such a horrible time with it, i ended up sourcing crimp type plugs. For belt and braces security i melted a little solder to each crimp before adding the heatshrink.
For the life of me though i cant remember where i got the crimp type DB37 connectors, but they do make life easy. The only thing that you must have are GOOD QUALITY crimpers. Cheapos just wont give a professional crimp. I invested in Hozan crimpers as i made a custom vehicle harness so had lots of crimps to do.