I left this up for 30 minutes. If you have them, this is a good test. Considering the duty cycle of your transmitter gives you a nice safety margin. You might consider using a silicon diode doubler to get higher voltage. Likewise you could use a doubler on the 60 volt winding to get screen voltage and plate voltage for the oscillator section.
Silicon diodes are cheap but high voltage capacitors today are very expensive.
A doubler might let you get away with two lower voltage capacitors. It shows you are thinking about what you are doing and are learning in the process. Making do with what is available is what homebrew amateur construction is all about. Heathkits may have been fun, but you really learned little building one if you followed directions and it worked the first time. We oldsters either screwed up, or in more cases than Heath liked to admit, they supplied a defective part.