Is there a replacement for the old 'Synth Bass 2' sound for practice files for voices?

Hello,
I use MuseScore for choral pieces, let's say SATB. My workflow is to create parts for each voice and export them as mp3 ini order to have individual practice files per voice type.

Even though the MuseSounds might be great and realistic-sounding, I'm not trying to get realistic-sounding mp3s. I'm trying to get mp3s which are as clear as possible so they are helpful when practicing. This is not the case with the choir sounds (of any soundfont, including MuseSounds).

The sound I still use to this day is 'Synth Bass 2' from FluidR3Mono_GM (which came with MuseScore up to version 2.1). It's great for exactly this purpose. It's precise and clear (even with multiple voices), there is no vibrato (opposed to string instruments) and a note is held exactly as long as the note says (opposed to piano).

I have these questions:
1. Is there anything similar to 'Synth Bass 2' in MuseSounds or MS Basic?
2. If not, what sound do you use for choir practice voices?
3. As far as I know, in MS4 there is no way to change the sound of my Soprano staff to a different instrument, right? So if I don't want a choir sound, I need to change the entire instrument/staff to something else? That seems pretty annoying. I'm still using 3.6.2 because it's possible there.

Thanks in advance