How To Drive Carts From Mod Boxes

Carts can be screwed directly onto mods, but is best avoided because of the following reasons ..

Maintaining Airflow - A standard '510' vape cartridge will screw directly onto most mods, but the problem is once they're screwed in, the airflow is often completely blocked off. Sure you can loosen off the cart a little to allow airflow but this doesn't solve the leak problems.
Leaks - On regular carts, the common leak points are the air holes, which are usually very close to the 510 thread. If carts are screwed directly onto mods, any leaks will go straight down into the mod's 510 connector which is definitely best avoided.

Using An Adapter To Solve The Above issues ..

Unscrewing the cart a tiny fraction will restore airflow, but doesn't address the leak issue. A more complete way is to use some sort of adaptor. Both examples shown below allow airflow through the cart virtually unrestricted and prevent juice leaking into the mod's 510 connector.

A '510 to Ego Adapter', designed to fit a range of Joyetech carts but also serves as a 510 to 510 connector. Available on Ebay Wish and many other online retailers.

A grooved heatsink available from Wish

Setting The Mod To Drive Carts
TLDR - Use fixed wattage (power mode) on 3-8W, with a suggested starting setting of 3-6W and increasing from there as required.

Update Nov 23 - it has been reported that leaking (from air holes) can occur during toking when using Wattages approaching 10-11W. Therefore pending further testing, suggest sticking to a max of around 8W. Please report your experiences on this via the Discord

Use Power mode. Carts are not designed for and don't need temperature control
Wattage Setting.Set your own mod box to between 3W to 8W in Power mode (some mods have a minimum power setting of 5W). Assumes a Ccell TH210 with resistance 1.46Ω, and the wattage calculated using the formula Wattage = Voltage² ÷ resistance in Ω (ohms)
If in doubt, start at 3W (or the minimum setting of your mod) and work up. If your cart contents are liquid and sufficiently runny, have had time to fully soak into the wick, and you're holding upright during the toke then a Wattage of upto a genuine 10-11W would theoretically be OK, but far better to exercise caution and think of 8W as a provisional maximum for the time being.
Caution: Be aware that your mod might not accurately deliver dialled Wattage at low-values. Start low and work up when you first try it
Caution: Take care that you don't inadvertently put a huge wattage through the cart, e.g. when changing settings. Even if the cart survives, it may start tasting metallic or burnt thereafter.