Dave welcome to the list.
So far, their have been two accessible watt meters made.  Right now, neither 
is on the market, but occasionally one shows up on the list.
The TW1 from LDG talks, is usable, unless accuracy is a major issue.  It 
does seem to be consistently in accurate however and is with in 10 per cent 
of the real reading.  Their also is a 2000 watt CW meter.  I think it is the 
p-2000.  I will be corrected if I am wrong.
Many hams still use a voltage controlled oscillator with  the voltage taken 
from across a watt meter.  This is very accurate in giving you feedback as 
you tune for forward or reflected power.  Highest pitch highest output.

The modern radios are light years ahead of those wonderful old radios that 
you are using.  Kenwood and eilcraft lead the pack, and you can pay from 
$8000 to $1100 for new radios that do not need tuning, have talking menus 
for just about everything, and internal antenna tuners.  I don't know 
anything about the yaesu amp, but it sounds like a big one.
Some icom radios like the 7200 have usable speech, and the ft-450 will talk 
the frequency.  Maybe a yeasu radio can do unique things with that amp, 
don't know.  Tentec has stopped respecting us, and yaesu never did.  So yes, 
you can do anything you want concerning station operation.  Yes you can 
spend what ever you want to do it.  I have handled the eilcraft radios, but 
not one that was set up for speech.  If you do competitive stuff, great.  If 
you rag chew with the boys, not necessary at all.  You don't need a race car 
to go to the grocery store.
Others will have input and comments.  Their was a used 590 here a week or 
so.  I have a 480, which I really enjoy.  Its a mobile sized 100 watt radio 
with a removable control head.  I am unwilling to put my hands on a 590, 
because I might not like my 480 as much after doing that.  I know "thal 
shalt not cuvvit another ham's radio" so by not knowing I don't cuvviteth.

Enjoy and you will find their is very little you can't do with out eyesight. 
you have to do many things differently, but they still can be done.