To the OP, Hook 'em!
Ok dude. I see you doing exactly what I did. Only I owned the W4. I went custom. Biggest mistake, and the most costly mistake of my audio journey. I'm relatively glad I have them, but I never use them.
BA drivers don't cut it for great bass. Some get really close. But if you listen to those genres which need beefy, live-air feel bass, BA's don't cut it. BA bass can be so taut and tight, you can bounce a quarter of it, but it won't bump.
Now, Multi-BA IEMS... well, let's just say there is a major group of growing people that think the multiple drivers smear the sonic landscape, and imaging, and create a congested soundstage. You're talking about a lot of equipment, crossovers, etc... built into each earphone. It's congested in there. So is the sound.
Now, customs themselves. Hopefully, you go to an audiologist, and they get your impression right. And weeks later, you get your custom from here in the US, or overseas. If it doesn't fit right, it is a nightmare. More impressions, more waiting. And the resale value on a custom if you don't end up liking them? Yeah not good. They might even fit you right until you eventually grow out of them as you grow.
It's my opinion you should be looking at top-end universals, which many think are better than the best customs. Maybe even more comfortable than having huge chunks of acrylic shoved up in your ear.
FitEar To Go! 334
Tralucent 1 + 2
Aurisonics AGS-2 (to be announced this week hopefully)
Ocharaku Flat-4
Any of these will offer great versatility, not to mention great, world-class sound.
You can order them, get them fast, sell them (or even return them!), and many people think you will get better sound, better imaging, and a better soundstage than you will with JHx.