As a truth fan, I love the attention to facts being invested in these spreadsheets comparing the two funds -
especially the wise remarks in the post explaining that which fund has better results depends on the starting and ending points of the comparison. End of year comparisons do not cover all comparison periods.
A bigger point, though, is that it's very hard to use past results to be sure which one is better. They're fairly close, but also the past doesn't prove they'll have similar performance in the future. I don't think that simply comparing past results of two funds is sufficient to decide wisely which one to invest in. This is especially true in a scenario where OP appears to want One Fund to Cover Everything. Based on the purpose, I would think the global fund is likely to be better than the US fund because, being more diversified, it covers more bases...but the US fund has even lower costs, which is advantage. Either way, IMHO (very humble!) the more relevant point is this:
An hour or two per year of rebalancing funds can measurably add some investment performance and stability. If you're not willing to spend 1 or 2 hours per year rebalancing investments in the future, just pick one of the two funds and leave it alone. The difference between them, at least to the point where comparing past performance can generate reliable prediction, is less than the "last 10%" that you say you don't care about. Both of them have verifiable low costs and middle-of-the-stock-road approaches.