+1 ^^, amen to this.

When setting up a rear hub axle setup, spacers and all, the shorter drive-side axle extension reduces the bending load on the axle, while having the cogs out more toward the drive-side also improves the chainline angle situation, especially when using the entire range of cogs while riding in the larger chainring up front.
Seven-speed freewheels are also a better choice than 6-speed freewheels for the greater variety of ratios and quality levels in the current market. It's getting harder to build or find a useful 6-speed freewheel for a versatile, high-performance road bike imo.

Depending on the bike's crankset and freewheel, a 9-speed chain often gives the most-forgiving shifting action while also not requiring that the front derailer position be "trimmed" as the chain is shifted across the range in back. 9-speed chain is my first choice where a 7-speed freewheel is used. 9-speed chain costs more, but is really, really worth it for the improvement in many instances, as long as it also gets along with the bike's chainring spacing.