How do I arrange a shower take off from my Heatrae sadia Megalife 210 vented cylinder as it doesn't have a normal male or female boss, ie for a Surrey or York flange. The hot water outlet is a 22mm stainless tube (integral with the cylinder) . I want to run 3 thermostatic mixer showers in total, so would like to have set it up properly. ie avoiding aeration and good flow.