Carb Advice Appreciated

Its going into a 67 barracuda convertible that will be used for Sunday drives and going to car events, never race or really push the motor at all.
With the cast iron exhaust and plain performer intake or even one of the weiands, the .443 lift Crane cam will probably make more torque and be more efficient for what you're doing. OTH if you really love the sound and feel of driving the bigger lift cam, then go enjoy it.
With the bigger cam, I'd want to know exactly which Weiand. Get the name and number.
a. Hood clearance can be an issue. Dpends on the aircleaner and hoodline but its somehting you want to check beforehand.
b. IIRC the Weiand I had was for a spreadbore.

thermoquad from a 74-77 440 truck, but I'm afraid that'd be over my head.

600 replacement carb for $540 (shocked me),

My suggestion is not spend money on a new carb at those prices.
I would choose the spreadbore carb and spreadbore intake or, go squarebore with squarebore intake.
For spreadbore a t-quad.
For a squarebore new I'd probably be looking at the Street Demon. It was more reasonably priced. Get the version with the phenolic/plastic bowl as it will better resist heat.
For squarebore used or used - rebuilt, an older Holley 1850 with the milder cam, maybe something like a 3310 with the higher lift cam.
Or Carter/Edelbrock but not the 750.