Mike,
I think it was you who said the simplest explanation is probably the best. Since no othe documents have surfaced - the alleged topo maps are a creation of the TePaul mind circa 2009 - I think its quite possible that the road drawn on the November 1910 WAS the working boundary. And, Francis was simply the first to recognize that widening it at 15 green and giving back land near 1 and 14 tees made a lot of sense and kept the acreage similar.
While the contribution was important to him personally enough to record in the 1950 history, he doesn't really say that it was the KEY to the whole design, just that it was his contribution. It simply was one idea that contributed to the final routing, not some huge aha moment, dramatic telling of it notwithstanding. (Wilson's trip got dramatized by the history author, too, and was mostly true, with dates changed, so why not put a little drama in Francis story?)
We also have to recall that we have made it perhaps a bigger idea than it really was because it became the focal point of DM's argument that CBM had to have routed the golf course. Even if they did lock on to the November 1910 boundary and/or keeping it to 117 acres for cost reasons, it really was just probably his idea to configur the holes in that area as they were, as opposed to Wilson or someone else doing other ones, so he told the story when asked.
To answer the question above, I believe there was no actual defined acreage in the Francis Land Swap - a phrase we need to stop using if we are to understand this. Francis didn't say there was a swap. Francis said that the fine homes along golf house road were once in the golf property, but now aren't because he needed more land up in a triangular parcel near 15 green and 16 tee.
We should really say that the land was "finally configured" after the best routing was determined. That is what happened, IMHO. That is the notion that the record BEST supports, IMHO. To conclude much else, we have to speculate far too much.
There was an approximate road, known to be necessary to reconfigure. They started with the Nov 10, 1910 map agreed to on a vote on Nov 15 (I think) AND a target of 117 acres from HDC, which was undefined past that map.
They went to work using that as a basic concept. They finished routing the course after visiting CMB in March/April 1911. After they picked the routing, they drew GHR to fit the holes. It simply turned out that the parcel required after designing it as they wanted to went up 3 acres in total. The did a deed reflecting that fact.
The land was configured to the golf course like a glove. There was never a formal swap. That is a DM phrase.
Do we agree on that or am I smoking some dope, having been off here for a while?