Can't really mail it but can give you a disk image that you can run in emulation or copy to a real disk yourself.
#DOS 2.5XL master.atr 130.02KB
Note this DOS is the "2.5 XL" patched which will only work on >=64K machine, it uses the Ram under OS for MEM.SAV.
If you want to just use with a normal DOS, copy the files "ASM" and "AUTORUN.SYS" onto another Dos boot disk.
The Autorun checks if you've pressed the Space bar during boot. If you did, then it'll load the assembler automatically for you.
Otherwise you can binary load it from Dos. You can switch between Basic/Assembler pressing Shift + Reset. Note you lose your program if not saved when switching.
I'm not sure it works 100% properly if you boot up with Basic disabled.
Also note it puts some vital program code (the reset handling) just before the Display List at top of memory.
If you use any graphics mode that creeps lower than a normal text screen (ie most of them), it'll wipe that code and the machine will likely lockup when you press Reset again.
To get around that, either POKE 9,1 or equivalent in the Assembler debugger.
Also you can load program ASM2 which will re-establish the reset handling. ASM must have been previously loaded to occupy the Ram under Basic.