I LOVE seeing so many MX/IPV3 users here!!! I've been using the MX since early Oct (MXv1) but just got my IPV3 this past week.
I've been messing with larger kanthal since I got my IPV3 but when I was running my MX1 on a mech the sweetest 26ga build was parallel coils, 4.5 wraps (9 total) at 0.16 ohm - 1/8". Great density, fast ramp up, and it didn't make my atty super hot like some builds I've done. I hated to pull that build out when I went to 22ga and am still searching for a comparable build with lower gauge wire. Start at 60W and see how high you want to go. I was running that build at over 100W on a mech but it liked more like 60-70 on the IPV3.
I'd vote for larger diameter coils and I use Yosh Vapergate's wicking method. If nothing else it keeps the dry hit from sneaking up on you and making you want to quit vaping forever and/or commit suicide.
Chuff caps are your friend. I'm not sure if anyone is making one for the MX just yet but...
Tobh chuff cap + 80 grit sandpaper + 30 min of your time + the O-ring from the MX top cap = bigger clouds.
Let us know what ends up working for you.