"I am not quite sure how to translate this to volts at the output. Or
can I put in ten watts and only see the needle twitch on a 30 Watt FS
wattmeter at the output and consider it done?"

Neutralizing a triode is not rocket science. If you are using a final with
a lot of plate dissipation, they do not get hurt when the neutralization is
not right. In the old days, many hams simply fired it up and tuned the NC
until bad things stopped happening. they did it with high voltage on. Some
of them got shocked.

A 30 watt FS output meter that barely twitches when driven by 10 watts and
the NC tuned for minimum may be enough. All you need is good enough. No
extra points for perfect neutralization.

To test, put a load on the amp and remove exciter. Turn on and tune input
and output tuning and see if it takes off. If it does, back to neutralizing
step 2. If it works as supposed to, then connect the antenna and start
calling CQ DX.

73, Colin K7FM