I made the crankshaft first, that's probably the most demanding component in terms of time and patience. Mick Knights has published his build of a x2 version in ME. I seem to remember it took Mick (as a real machinist) 18 days to turn the crank.
I certainly can't build this to a deadline, it just has to happen when it happens.
Yes the tapping of so many 10 & 12 BA holes (and tapping out 14bA nuts @12BA!!) is something to look forward too (NOT), but I'm sure it will be character forming. I was going to build David Parkers Vega Twin, but then I thought I might as well go the whole hog and build one of the real classic engines.
My engine blog is here:
http://whittlev8.wordpress.com