another dim light bulb moment, and i think i got it this time.
with a pitch of 1, this gives 4" lead with 4 starts as the lead is number of starts times pitch. lathe is set at 1/4 tpi as required
this is right, and i'm trying to write an explanation, but it is so hard for me to articulate. for example the first thing i say in my idea above is "with a pitch of 1". i give no citation as to how i came up with this figure and it appears i snagged it out of thin air. however, now that the numbers are written down, they can be run through and proved correct so it really doesn't matter. i suppose as long as you have an understanding it doesn't matter whether or not you can articulate.
what makes it so odd to explain is that it was figured using the relationship between the required lead and the required setting the lathe at 1/4 tpi. this is NOT the order that most screws are figured in, but it had to be done this way with this screw because it is so different. while i did figure it out i'm sure there is a better way to understand this.........