Josh got the xv68k emulator (https://www.v68k.org/xv68k/) sorta working on the Silver Mill config. “sorta” == no pipelining, inlining, or vectorization, pre-alpha code gen quality.
Xv68k emulating itself emulating a hand 68k-assembler version of helloWorld takes 55335 68k instructions executed. The same emulation run on Silver takes 16954 Mill instruction bundles executed. Most of that reflects Mill width, but Mill used only 41482 instruction operations, reflecting a less loquacious ISA too.
Granted, the 68k ISA is a pretty easy target, but this seems encouraging.