I flew both the 707s.and the DC8s.
Includes the early 707-320 with JT-4, and the later DC8-60/70s types.
As far as pitch control "muscles", they required about the same.
Rudder, your legs needed about the same effort...
a lot of muscles.
The big difference was the ailerons. Took twice as much muscle with DC8s.
The nicest flying DC8 was the DC8-62...
I liked the DC8-73... but just because of the CFM engine power.
Yet, I missed the 707-320B/C when I went to the DC8s.
Gross weight of the 707-320C was 334,000 lbs MTOW (sorry, I had pounds).
The DC8-63/73s grossed at 355,000 lbs MTOW.
xxx
Happy contrails