I use the 22 mm Digiflavor Siren with the Subox Mini-C all the time. They work great together. I use either 26 ga. Kanthal or 28 ga. Kanthal exclusively. If you buy either 26 ga and 28 ga. kanthal, you are buying regular, round kanthal wire. You don't want the flat or ribbon kanthal to make the type of coils I make. If you are not familiar with building your own coils, I think 26 ga. is a little bit easier to work with.
For the Siren, I highly recommend you use a 3mm rod to wrap your wire around, which will give you a 3 mm diameter coil. With a 3 mm diameter coil, you will be able to stuff more wick in there, which is what you need for the Siren to make sure you do not get juice seepage through the airflow control. I usually make 10 or 12 wraps and then, while the kanthal is still on the rod, put it next to the screws on the build deck to see what size it should be to easily fit between the screw heads. Then, use needle nose pliers to unwrap some of the wraps on each side until it's the right size to fit.
I always make a slightly spaced coil, which is very easy to do. If you watch the more recent Phil Busardo you tube videos, you can see him make a slightly spaced coils. I do it the way he does it. While the coil is still on the 3 mm rod, I put my thumb over one of the coil leads to hold it in place, while I take needle nose pliers and grip the other lead and gently pull it outwards. Don't pull it too hard, or your coil will no longer fit between the screw heads. You can use your fingers to push the coil back together if you've stretched it too far. Then, use an ohm meter to make sure your coil gives you the ohm read you want. The coils I make are anywhere from .9 or 1.0 ohm to 2.0 ohms, but are usually around 1.2 ohms.
I'm a big fan of the Coil-Master DIY kits. It makes coil building much easier because it has a great coiling jig, and everything else I need, including an ohm meter all in one easily transportable kit. Once you have this kit, the only other things you need to make the coils I make is the 26 or 28 ga. kanthal and Japanese organic cotton pads for wicking. You can probably find a better price for this kit from another vendor, but I recommend you get an authentic kit, whether it's an authentic kit from Coil-Master, UD or anyone else.
Coil Master DIY Kit V3 - Coil Master
Good luck with your Siren! If you want to read more about the Siren, visit our Siren thread!
Digiflavor Siren GTA