Plan was, sort of still is, supplement FM9T as both a pre- or post- depending on need (patch) using both of the SPDIF I/O's on each unit.
But since I got it and did a quick test with my FM9 I've been using it all by itself using a small DAC headphone amp that has SPDIF input and one expression pedal (Mission SP-1).
I could see myself gigging, if I still did, in my mid 70's now with a crap tone of health issues - me and wife both, with just a VP 4, a light weight clean solid state amp like my Cube 80GX, and an expression pedal or two - one dedicated to volume the other for mainly wah but also rates, depths, or delay time or feedback - as needed. I've haven't needed the "wall of amps" sounds and distortion since the 60's when I thought I was Hendrix. More of a jazz guy these days with some "classic rock" thrown in.
I'd have killed for a VP4 in the 60's! Love this little unit and I've said that in other posts.
Funny my FX3 has sat lightly used since I got my FM9T, now it seems the FM9 might sit less used with the addition to my floor of the VP4.
Larry
Edit - I'm seriously thinking of buying a second VP4. The first as the "addon" to my FM9T as originally planned, the second as a small stand alone "rig," or practice unit, as described above using a small DAC headphone amp. Then I can keep it in my shop where I can put down my elrctronics projects or reloading efforts and relax with some nice low intensity jazz with a touch of reverb, delay or a little (very little ) this or that fx.