I'd have to throw my vote behind getting it running before you do anything else. When was the last time it was run? is it seized? if the frame has been altered, probably a waste of time if the motor is also no good, except for the educational experience and sentimental value.
Kinda hard for me to say which is more comfortable, I have a hard ass. Put lots of long distance miles on my Suzuki380 with clubmans, I was younger, the seat was OK but it was hard on my wrists then, wouldn't wanna do it now. Choppers and cruisers were theoretically designed for long distance comfort, but "comfort" is all about your body type, size, and what you feel is a comfortable position for your seat and upper body to remain in for extended periods of time. The nice thing about a project is you get to make it fit you. Sometimes on long rides, I don't feel like stopping, but feel the need to stand, so I just stand up on the pegs for a while, work the leg muscles a bit, kinda fun at 70+mph, but it's hard to do that if your leaning forward on a cafe, or if your pegs on a cruiser are so far forward you can't stand up straight. My daily 750 has a somewhat thinner than stock seat and "superbike" bars, and is probably the most comfortable bike I've had since my stock XS650. Your seat looks a bit like the seat on my Fatboy, and I'd have to rate it "less than comfortable", OK for around town but not nearly as comfortable as I was expecting for distances.
Drag bars are "flat" bars, a slight curve to them for grip, but no "rise", Risers, sometimes called dogbones, are used to raise any set of bars higher than the stock mounts on the top clamp.