5U4G suitable for Dyanco ST-70?

There have been several threads at various times on the suitability of subbing a 5U4G rectifier tube for either a 5V4G or a 5AR4 in a ST-70. I asked Will Vincent, a respected re-builder of ST-70s (among others) for his opinion and received the following email:

Harry: Never use a 5U4 in a Dynaco 70.....The power transformer is rated for 2 amps on the 5 volt winding....The 5U4 is rated at 3 amps......Not good......Will

So, I thought I should pass this along...