[Johnson] Need cathode/plate meter advice for 1 tube xmtr project

[Cal Eustaquio]

All:
Been contemplating a 1 tube homebrew transmitter to match up with
these National (and other) rx's hovering around in my house. I plan
to run it on AM (yes, on a 1 tube transmitter no less). But I'm
"cheatin' a little": I'm using a two function tube, a 6LR8 that has a
triode and a pentode all under one roof. 

Here's the question: I'd like to avoid putting the plate meter in
direct line with the plate supply. Instead, I would like to put the
meter in series with the cathode circuitry so as to avoid high plate
potential normally found with a plate circuited meter.

Is their a problem doing my transmitter in this manner? I know I
would be including all currents (all grids plus the plate) on the
cathode. I'm looking for the usually dip in plate when tuning but
want to know if having everything measured at the cathode of the
pentode PA would present any problems. I await your candid response!

Thank you,

Cal, N6KYR.