Hi I have model in shape of hourglass. 2 bigger areas with smaller "tube" that connects it (just to as example to explain myself). I know that if i want it hollow i need at least two hole on each end. For now i have one 4mm hole on one side and 3mm hole in other. My question is if, in middle, i can have small tube connecting those 2 bigger area that is under 2mm? Now that tube is 3x1,7mm. (inside) Thank you, Marián