A Wisper is a good choice. It's one of the better Chinese bikes, and Wisper is one of the few brands which offer decent customer service. I'm acquainted with David, the guy who owns the company. He genuinely wants his customers to be happy with their bikes, and he is very accessible - his mobile number is all but public and he usually answers it. As regards comfort, you probably know more about saddle lore than I do, but the type of bike comes into it. I have a 20" wheel ebike which runs on the same balloon tyres as yours. The 'e' bit is irrelevant for this purpose, I've found the comfort of 20" wheels to be not quite as good as a 700c bike. It's pretty good, I've done 80+ mile rides on mine, but I feel those a lot more than I do on a bigger wheeled bike. The tyres need to be run at a fairly low pressure to take advantage of the air chamber suspension. It would be worth trying them at the lower end of what's printed on the sidewall.