Stop in for a cup of coffee

Good Evening All! I'm meeting with our builder on the 22nd for shop design. I was hoping to have more of what I want figured out by now but have been busy settling in on the property. I know it's going to be 30x40x12 stick built. I want two doors, wider than normal and one taller for my lifted Suburban or possibly tractor which I hope to buy in the future. I want to put a 4 post lift in it so I know it should have thick concrete but my builder is saying it could be better to wait and cut out the area later, then pour in the 6 inch layer. There won't be any plumbing, or loft. I want to have it "finished" with sheet rock and insulation, also want hardi plank siding. Also want a couple of windows and a man door. There is already a 200 amp panel existing for it on my H frame. That's what I have figured out, am hoping to get recommendations/comments on what I have and any ideas for little add ins that may be best done at the time of original build. Sorry for the long post, any input would be appreciated.
If you know for sure where you want the lift to be, then they can dig deeper pockets in just those spots when they lay the floor. Then you won’t need to cut and repour later. Sometime concrete floor guys think too linearly and it’s all to be poured at the same depth...but there is nothing that requires concrete to be the same thickness everywhere. Hell, they can even pour deeper blocks in those spots and lay the rest of the floor afterward.