I have four (4) Canadian Goodyear tires that are about that old with no wear because my Town Sedan was owned by (2) car collectors for (10) & (20) years, total of (30) years. I am still using them.
For the past 20+ years, Model A owners on past Forums have always commented on the great road handling improvement, no more wandering, and a far softer ride "after" installing softer "new" rubber tires.
On very "smooth and level" paved highways ............. there is not much Model A riding difference between that of having solid rubber tires ......... old Model A hard tires ........... and even new softer Model A tires.
On the other hand, if there are uneven road patches, un-level pavement construction seams, dips and bumps, or other very noticeable road surface irregularities, with very old Model A (40) year old hard tires, (even at 35 mph), it takes both hands to hold the steering wheel ............ accompanied by 100% concentration ........... to avoid looking like a wandering, one-eyed drunk driving at midnight ......... while wearing a welding helmet .......... accompanied with (4") of play in his steering wheel.