Well like the others I have found out there are a few things to getting a 6-banger up and running.
I usually set the mold on top of my pot while it's heating up, then start out by pouring the first three holes, then allowing the boolits to sit in the mold and spread the heat a few seconds after cutting off the sprue. Then as mentioned move a hole at a time until everything is up to a good temp.
Speaking of temps, I purchased a pot thermometer as well as a little digital one that inserts into the end of the mold via a drilled hole. This has helped out dramatically in the consistency of my boolits, in both less numbers of throw backs but also in weight. It took a bit of playing around but I have the temps for my alloy and mold recorded so it only takes a couple of pours and it's a done deal.
Here is a link to my simple temp/weight testing,
Analysis of cast boolit weight variences
THis one is to the digital thermometer I am using,
NOE Digital Casting Thermometer
The first link is a to a pretty informative thread. It did show me that the temp will effect the weights, and that a constant pressure on the handles will as well. Nothing overly scientific, but it has helped me to narrow down a few things I was not paying attention to.
Yep, broke a handle as well, and it wasn't hard to do, it went with very little effort and I was pretty much like ***. But like mentioned Lee was understanding and shot me two new ones to replace it ASAP. Luckily I had several so I simply pulled off one of the others and went on with my business.