I always thought the K8 was Honda's best 1-rider 750, having the nicely dipped (front) seat design they had started on the GL1000. I saw lots of touring with the K8 bikes, always single riders. by 1976 there was a huge custom-seat industry, spawned by lowered front seats for the earlier 750s. I even designed and built my own (which is still on mine) in 1981, following their lead.
Everyone hated the 630 chain, though. It was noisy, short-lived and expensive (even the early O-ring version): the 'conversion' sprockets appeared by 1981 and sold well, usually sporting the Diamond XD chains for longer life. The 17" rear wheel's larger tire footprint handled the touring loads well, much better than did the 4.00x18 rears of the earlier bike: it didn't wear out the rear tire in a single trip, then!