I have the Yihi Sx mini Q mini.
You need to build above 0.1 Ohm, and make sure to use two very good batteries, like VTC5a or the P26.
I have some mods, and only the Dani box is able to drive a true 0.05 Ohm coil without complaints.
The vast majority of vapers use coils with a resistance higher than 0.15 Ohm. The efficiency of ANY mod below that value can quickly become risible, despite what is stated in their spec sheets.
Personally, I don't use or build coils below 0.25 Ohm, be it on regulated or unregulated setups, as it is inefficient - and considered dangerous by many.