Ooh, never thought about narcosis increased risk.
What has (kinda) worked for me:
Start dosing dramamine about two days prior. Apply patch night before and take half a chewable dramamine the day of.
USUALLY that's sufficient and I haven't had ill effects from the drugs. I've been down to 80 with that combo and didn't feel anything. I've never experienced increased dosing (though never thought of it), nor, weirdly, have I ever had one come off except one time in the PI, which I didn't notice because the waters are FLAT there. In fact, after a trip out, I was at work two days later wondering why I had dry mouth, reached back, and sure enough, there it was.
My only symptoms are being dried out (need lots of water) and VERY slight blurred vision for close objects.
Isn't always sufficient though. The hour long trip down to Big Sur on a 12' swell day had me puking over the side. Which reminds me, etiquette for throwing up off an ill equipped boat? No easy way to do so on this one, I ended up having to hang off the side over the tanks with the valves sticking into my gut. *That* helped.