lost wax casting flask sprue base

I have slowly been making the equipment needed to do lost wax casting. I am making a 4in flask and decided to go ahead and make the rubber sprue base. This is made for a 4in O.D. flask. But it could be scaled to any dimension. Obviously printed in Ninja Flex. I did 3 perimeters, 2 layers tops and bottoms, with 25% infill. I should have done 3 layers top and bottom, but it still came out ok'ish. The extruder jammed on the solid layers in the bottom of the part (you can see in the pics), I'll either reprint it or coat it with black RTV. My flask isn't done yet. I still have to make and weld on the flange. Which reminds me, keep in mind I designed this without knowing any 'standard' measurements. This is 15mm deep, so if you are making it for an existing flask, and the flange is less than 15mm from the end, you should scale this height wise to fit. Hopefully this all makes sense.