Any advise to make that better or doesn't that really matter? Maybe place it upside down ?
They get hot on the bottom because the hashing module is screwed to the heatsink and the heatsink is screwed to the bottom of the case. As the heatsink is not touching the top of the case, the top does not get hot.
The internal fans should do the job of keeping things cool, the bottom will not get hotter than the heatsink anyways
You can add additional air cooling externally on the case bottom if that makes you feel more comfortable.
Keep the case horizontally. I would not flip it upside down, that would make the hashing modules hang from the top, it was not designed for that.