NICE!
Great idea.
I've joined a discord group that's also setting up SOP's and one set is the radio comms.
This is much better than I've seen anywhere else. Only problem is we can't send numbers.
The other group suggested just using the first two letters of each number i.e.
1 = on
2 = tw
etc
My only suggestion is that we should also add course and speed on too.
So in your example given course of 310 and speed 18
POSxAFxFIONFONIXEITHXTWTHXTHONZEXONEIZE
Unless of course, numbers are being added as recognised characters and then all is good.