The ones you mentioned like Stilz are simpler no pit, etc.
It's been about 25 years since I built a remodel shaft but back then I built about 20 of them( with another guy, he was the boss). We built a lot of them in churches and Legion type halls. Not as daunting as you might think. I doubt codes have changed a lot. We were working with the winding drum type(cable and motor in separate mechanical room). Double 5/8" type X on the shaft. A double (LVL) for the rail to lag to. Knocked down drywall frames for the doors. You prob need a 4' x '5' area. Dig out the pit, form up and pour foundation/pit, frame up under the floor joists, cut out the floor joists, move to next floor. Hang drywall and install doors. 2 stories and a basement is pretty easy. Now I think they offer systems with an overhead motor so no need for a mechanical room. You could always build the shaft then hang some floors in it and make it a closet for when you're ready or to break up the cost.(I think the closet idea was suggested by a member already) Prob be a good selling point for the house. We used to use a plumb bob. They would be perfectly plumb over 5 stories.
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