With the understanding that I don’t have any actual experience using an H90 with an acoustic bass … and assuming we are not talking about a stand-up bass (a double bass) … and assuming you’re interested in relatively subtle enhancements of your acoustic sound:
I’d start with EQCompressor (EQC) serially running into SP2016 Reverb (SPR).
EQC has a lot of factory presets and many of them are specifically for bass. Two things about this algo: 1. I play guitar and like subtle compressors. Although transparent, this compressor will squash more than a 20 ton vice so I use it set VERY low. Maybe bass calls for a lot of compression? I don’t know. I’m just saying that this thing can SQUISH! 2. In the H9, EQC had an awesome graphic display that is not in the H90 Control software. If you plan to explore EQC in depth, I recommend you install H9 Control software and run it in demo mode so you can see all the factory presets and how moving the knobs affects things. Just playing around with the H9 graphic display will help you get a feel for what the knobs do.
The H90 has a lot of great reverb algos, but SPR has become my favorite … especially for subtle/natural enhancement. There are 1000 options but I would start with something like Type= Vintage Stereo Room … Position= 67 … Diffusion=67 … Decay .5s – 1.5s … Pre-delay … 20-70 ms.
As an alternative to EQC you can try Sticky Tape (probably with the W&F Amount and Rate set to zero). There is a compressor in there that is fairly subtle. The filter knob and tape speed will both provide some EQ. The Offset and Width can add some thickness and stereo spread.
Hope that helps.
