OK, so you're trying to min-max for minimum downtime?
As far as worrying about the soft control, right after they remotely shut off your meter, just break the seal and physically pull the meter. When done, reinstall it and tell them you pulled the meter. Next time they're in the neighborhood they'll slap a new seal on it.
Meter-mains change everything
A huge factor in this question is the NEC 2020 requirement now requiring disconnects outside (for fire department use). Economics dictates that this happens as a "Meter-Main", or combo device containing both a meter and main breaker. The AHJ might force you to do this for a panel swap.
So. The best course of action for someone seeking to maintain internal control on a panel swap, is to change out to a "meter-main" first. That is a very simple operation.
- (prep) Obtain an accessory ground bar for the Old Main Panel (soon to be Master Panel)
- (prep) Install a bonding jumper between neutral bar and accessory ground bar.
- (prep) Move all grounds to the accessory ground bar.
- (prep) Run a 4th ground wire from Old Main to meter location.
- (LIVE) Have the electrician swap the meter pan for the meter-main, coordinating with the utility.
- (LIVE) Remove bonding jumper from Old Main, now master subpanel.
You now have local control over meter shut-off. Turn off the main breaker at the meter, and the "Old Main" is now fully de-energized and you can do anything you want with it, anytime you want. I strongly believe this is very worth it for DIYers who want to work on their own terms.
You are also in compliance with NEC 2020.
Knock-on effect: Panel Placement. Prior to meter-mains, the run from meter pan to Main Panel was energized at all times and entirely unfused. If you drove a nail through it, BOOM. As such, this wire was required to be as short as possible, forcing you to place the main panel in a specific location relating to the meter. With meter-mains, this requirement is gone. The panel can now be anywhere - you have freedom of location. Speaking of that.
A new panel must be properly located
Service panels and subpanels require a working space the width of the equipment (but at least 30"), 36" deep, 78" tall, not on stairs or awkward surfaces. This space must be kept clear at all times. It cannot be in the swing of a door and the panel doors must be able to open 90 degrees. I recommend a place that's likely to happen naturally, such as a hallway or threshold. In fact some AHJs require that!
So just because your old panel was there before, does not mean your new panel can go there.
Speaking of location, consider a subpanel, or an inverse subpanel.
Since you say your #1 interest is getting more breaker spaces, the simple answer is "subpanel in a location of your choosing". Run some 2-2-2-4 between them, 90A wire, easy peasy.
Now if you want to integrate that into a meter-main upgrade, you can actually "flip it". Install a subpanel and interconnecting feeder like normal, except, run new main wires from the subpanel to the (new?) meter location. So when you do the cutover, you are making the new panel the main panel (or master subpanel), and the original panel becomes a subpanel of the new. That saves you having to rewire the old panel, and if its location is faulty, it's still grandfathered.
New meter, mast and weatherhead
Another way to do this swap, depending on what you're trying to do, is to build out a new meter pan, mast, weatherhead and main service/feeder wires to the panel location of your choosing. They could be right next to each other or clear across the house (since meter-mains allow indefinite main feeder length).
Then, on cutover day they are simply moving their service drop from the old weatherhead to the new one. It's a single operation for them. Meanwhile you cut over the service entrance/main feeder wires from the old to new.
This could continue to feed the original panel, or feed a new panel with any of the concepts above.
You now have a dead old service entrance wire, weatherhead, mast and meter pan. Demolish at your leisure.