Hello Chadsticles

A warm welcome to these forums.
What a spectacular lawn!

I can't help but feel this is the wrong mower for you.
The Thoroughbreds were decent machines, designed and manufactured
at Eagle Farm, Brisbane. But . . .

This particular machine does look to have had considerable work,
with a re-manufactured catcher (the original was plastic).
The problem with the Thoroughbreds is that no parts are available.
So the condition of reel and bottom blade will be important.
[Some Competent repairers can make new blades from stock though.]

Given that it takes you 2.5 hours to cut the lawn (with 18" rotary),
a larger reel mower would be more suited. The Thoroughbred was also
made as a 16", but the best 'classic' machine would be a Model 45 17",
because it is a great design and parts are procurable.

p.s. Also check the engagement speed of the primary clutch. Worn shoes
require a higher RPM for engagement. The Scott Bonnar is a more
'relaxed' machine in that its primary clutch is a positive, cone
type, requiring less RPM for successful engagement of the cutters.
Both machines have very reliable - and similar - roller clutches.

Hope this helps.
-------------------------
Jack