On that particular board -- ALL high current connections are to the bottom of the board, there are no high current connections solely on the top of the board so through holes are never a problem. Majority of connections on top layer are test points, MOV connections, a couple low current connections, one redundant high current connection (GI) plus lots of redundant ground connections.
Don't worry about the HV voltage -- that one has a typical range but in real life, he varies quite widely depending on his load.
The switched lamp voltage, on the other hand, is an issue.
When you power this up - what is connected to J1 and J3?
Particularly J3, pin 6. J1 pins 3, 7 and 9.
With fuse F1 pulled -- can you measure the AC voltage between E9 and E10?