'66 Valiant Running Hotter than Expected

Too late to try anything 'til the temps come back up, but I'd toss a 5-blade fan on, or put a 7-blade with a thermostatic clutch on. Cruising at 80 a 7-blade turning 3,200rpm could actually be hindering flow some, could explain the bugs hitting the wall of radial airflow w/o passing through...but the condensor could be a real issue also.
I know You are thorough, and it's new, or looks like it. If the fins are nice & combed straight, it shouldn't be an issue, but if the system is just enough to get it done w/o it.....
I love Your car & how it looks, You may have to add seals to be sure all of the air through the grill goes to those exchangers tho', and a modest chin spoiler at the rad. support will add air pressure & volume in frt. while creating a low pressure area under the engine compartment to extract it.
I did that to My ex Popo Dippy, because 4.89 gears & 4,000rpm@65mph w/a 4 gear was puttin' a hurtin' on the rad. I had in there.!!
Good luck & keep Us updated!!

Yes, hours combing the condenser.