I think most caps should be ok due to the rubber pad they sit on. The snap in caps don't have this but still be careful.
I think you might run into some problems with seven transformers inside the amp section. Ideally you should have two of them, each with two 6.3V windings just for the CCS tubes. The rest should be in the PSU box. Also EI cores are the worst when it comes to magnetic fields which is why I'm looking into R or O cores for this.