Here in Poland non-standard channels are actually standard, the 6 GHz licensed band is divided into 28 MHz wide channels with 29.65 MHz spacing.
But the SXT6 and DynaDish6 is ar93xx (not ar92xx) based, so custom channels are not supported. Any plans to support them?
The products work as is (nearest multiple of 5 MHz center with 20 MHz width will fit within the correct 28 MHz wide channel), but 28 MHz width with exact center freq could use the otherwise wasted spectrum to get 40% higher data rates (almost like AC).
The hardware almost certainly can do it, UBNT does (not any random width possible due to software, but 5/8/10/20/30/40 MHz supported, same on both XM=ar92xx and XW=ar93xx board types).