And you’ve struggled with soft speech, yeah? But realistically it depends. Your hearing loss needs significantly more headroom than the manufacturer guides will show because of your conductive loss, and the manufacturer guides are optimistic anyway. Additionally, you need a good fit with the mold to boost the lows that you’ll want and optimize feedback management in the highs. This isn’t impossible with a RIC and a custom tip, but it depends more heavily on the individual ear as the fit and retention on a custom tip often isn’t as easy as with a silicone mold. Still, if one has a REM system it is easy to identify the problems and either compensate for them in the programming or initiate an exchange. But if one has to fit a hearing aid blind, as one does when they don’t have a device for real ear measurement, it’s worth optimizing everything else as much as you can.
But yes, a RIC could work. Chances are higher that it will work well if you have a big ear canal with a good bend in it to hold the custom tip in snugly.