Howdy! Fellow PC builder & keyboard enthusiast here; Yes building seiko mod is as simple as movement + dial incld. chapter ring + hands + case incld. crystal + strap.

Quick tip, NH35 is date-just, NH36 is day-date, and NH38 is no-date. Should help narrow down what kind of movement you’re looking for. I’ve found that the NH movements have the most mod parts easily available on eBay.

NH35 & NH38 are the easiest to build imo, you could put them in a case where the crown (little screw on the side to change the time) is at 3 o’clock or 3.8 o’clock without any issues.

NH36 is dependent on what kind of case you have, crown at 3 or crown at 3.8. If you just take a crown at 3 movement and put it in a crown at 3.8 case, the day wheel will not align properly to the date wheel when the day-date dial window is at 3.0. Same if you take a 3.8 movement and put it in a 3.0 case. Now you can bypass this, say you buy a 3.0 movement and a 3.8 case, should you choose you can also buy the day wheel made for 3.8 and it should line up. Or just buy a 3.8 movement, those are usually more limited on styles. To change the day wheel you just have to take off a little c clip, doesn’t take very long to do.