Boost Chainline and 1x Boost Chainring Selection

Boost spacing is here and quickly propagating across many bikes.  Wolf Tooth wanted to level set everyone on what Boost means to chainline and chainring selection for 1x drivetrains. Note that there are other issues with widening the rear hub spacing on 2x or 3x front shifting drivetrains that are covered well by BikeRumor and this won't be discussed here.

For those not familiar with what "Boost" is, it really just refers to a widening of the axles on mountain bikes.  From 100mm to 110mm in the front and 142mm to 148mm in the back.  The increase of "only" 6mm in the rear axle (3 on each side) was chosen because in most cases it is as wide as the axle can get without going to wider Q