You wiki document makes no mention of Qsynth. I use it in conjunction with FluidSynth and Frescobaldi on LinuxMint and MacOS (I use CoolSoft Virtual Midi Synth on Windows):
https://sourceforge.net/projects/qsynth/files/qsynth/0.5.0/I personally find using Qsynth the best way to manage Fluidsynth. Qsynth allows me to specify easily multiple soundfont files, reorder them, modify Fluidsynth volume output, Reverb adjustment, and Chorus adjustment with its UI. It also allows changes to the base sound engine Fluidsynth uses (ALSA, Pulseaudio, Jack, etc.) from its Settings. And it runs Fluidsynth only when Qsynth is loaded. Fluidsynth's CLI syntax, of course, can do all of this, but with a substantial learning-curve working CLI. I'm normally a CLI guy (long years in IT many of them as a ERP app admin) but sometimes a GUI is better (e.g. Frescobaldi :-)