Do you mind to let me have a copy of your schematic for reference?
Two years ago, I had the same idea to build a SE amp with ballon tubes. I tried 227 to drive 245 with 280 being the rectifier. The result was not good because the gain was not enough to drive my speaker well. I thought that the problem was with 227 for it is a medium-mu triode having a mu factor of 9. I then replaced it by 12ax7 which has the mu factor at 100. The result was better. But that tube line-up was not what I want. So, it has been put aside for two years.