Just in case someone finds this in the future. I went the recommended route and manually extend the allowed area in bed.g like this:
bed.g
[...]
M208 Y{global.minY}:{global.maxYMesh} ; extend allowed space for probing near the edge of the bed
G29 S0
G1 X400 Y{global.maxY} F20000 ; Park
M208 Y{global.minY}:{global.maxY} ;reset safe moving space to normal
In config.g I create the referenced globals from above:
[...]
; Axis Limits
global minY = -149
global maxY = 72
M208 X-146:159 Y{global.minY}:{global.maxY} C0:250 Z0:290 ; set axis minima & maxima
[...]
global minYMesh = global.minY
global maxYMesh = 115
M557 X-146:150 Y{global.minYMesh}:{global.maxYMesh} P10 ; define mesh grid
[...]
This works fine and is maintenance free in terms of having to maintain hardcoded coordinates in multiple places. 👍