IIRC I always had Mozilla dictionary add-ons/plug-ins for FF/SM, and I'm not sure if I want to know where Hunspell data files have to be saved. Typing, FF and a 1 GHz Pentrium III CPU may be a fatal combination, but I tend to use and prefer SM anyway.
Hunspell may be faster than Mozilla's solutions, but it works with nothing but the DLL installed. It wasn't an intentional and tested choice (speeds, memory usage, ...). It was a matter of installing nothing but Yet Another Required And Unimported DLL, which worked.
I added LIBPATHSTRICT to my xxturbo's and they can co-exist. The original mozturbo doesn't have this and would need wrapping in a script to set LIBPATHSTRICT and BEGINLIBPATH if you want it to coexist with my builds.
Recently I was testing FFTURBO.EXE XOR SMTURBO.EXE, and MOZTURBO.EXE. I'll try to assign LIBPATHSTRICT=T and BEGINLBPATH=xxx to the MOZTURBO.EXE object in the <WP_START> folder first, with the same xxx an own install script assigns to Mozilla object(s) installed by eCS.
If that doesn't work, then I'll write a script. Perhaps even a delay (command "SLEEP.EXE 1 & SMTURBO.EXE") could work, to avoid some race condition or whatever.
FWIW: SYS2070s always happened with SMTURBO.EXE (not used with FFTURBO.EXE), after probably less than 5% of boots, it seems like SMTURBO.EXE was no longer in the tasklist when the SYS2070 popped up, and a reboot was required to browse.