While it is possible to run a 3/8" line off of our pressurized transfer fitting for use as a blow-off hose, we do not recommend it. The diameter of the outlet tubing on that fitting is narrower than we'd recommend for most beers - especially those that have the potential of going volcanic on you. If you are expecting a high krausen fermentation, we would recommend going with a larger diameter.
On the Brew Buckets, we recommend using a dedicated blow-off fixture like the Hose Barb | ½” 90° for Blow-Off fitting (or even just 1/2" ID tubing straight into the lid) on our Brew Buckets.
On the standard Chronicals, we recommend using a 1.5" TC to 1/2" hose barb elbow to prevent kinks. Clamp this to the top of the lid and run 1/2" ID silicone tubing off that barb. Now you have a kink-free blow-off tube setup.