Shiny isn't always a good thing. Shiny can mean a cold mould and possible pout fill out.
Some light, even frosting can be good. I tend to like it. What I want to avoid is a heavy, pitted looking frosting. I also want an even frost over the entire bullet, uneven frosting mean the mould has hot spots.
Mould temp is mostly controlled by casting tempo. Cold mould means you need to go faster, too hot means go slower. A small fan blowing on the filled mould helps with too hot. Bottom pour vs ladle makes a difference.
Experiment with how long between pours, is it every 15 seconds? 20? This matters to each individual mould. Find what that mould wants and all is good.