As Bruce said, I don't think that your problem is solely due to low temps. Make sure your developer is not contaminated, diluted correctly, mixed in the correct order, etc.

Trays are faster and easier than drums. The only hard part is pouring them back (at least a few disasters.) You can process multiple sheets at a time (two is easy, more is possible) and start a new sheet in the developer before another is out of the blix.