Shouldn't be a problem with the octal tube rolling, but I have not tried the 6CG7 tube in this product. The circuit is a bit different than that in the Transporter. I have a few ideas cooking though....
As far as the EML tubes in the PS 36.5, the PS boards would have to be raised and this would also require a revision of the heater heat-sinks as they are a limitation right now as to how high the PS boards can be raised.
Thanks,
Dan