Best practices for using a steam cooker?

I have this style of steam cooker that I got from a chinese store previously. It's mostly used for steamed dumplings AFAIK I've been using it to steam fish, and I can't help but feel like I'm not using it properly as it seems to take longer than expected to steam the fish to 165F, and the heating is very even, e.g., some parts of the fish would reach 195F before others hit 155F. Here's a pic of my set up: https://imgur.com/pCRnC3z Is it an issue that my plate covers almost the entire surface? I feel like it prevents circulation which is probably important for steam cooking? Any suggestions on how to properly use this? In this particular case, the fish is almost as long as the diameter of the cooker, hence why I need a bigger plate. I guess I could cut the fish in half and put it on a smaller plate? submitted by /u/Diligent_Board_172 [link] [comments]