LAN upgrade on the horizon-- Catalyst 3750 to Catalyst 9300

Hi folks!

We are going to be replacing 245 switches on our campus at the end of the year and I am looking for the best way to get our configurations deployed to our new equipment. So far, I have considered:

• Notepad++ with highlighted variables that change on each switch
• Getting a bit more familiar with Python to do something fancy (I have a lot of learning to do for this one!)
• Using a Cisco config conversion tool
• Trying to set up APIC-EM and having it work across versions
• Creating an Excel Spreadsheet full of wizardry that will allow us to enter variables (VLAN's, IP's, hostname, etc) and shoot out a configuration

If you folks were in my spot, what approach would you take? As a note, we are allowed downtime for this.

Thanks for your input!

Edit: Regarding personnel---we are a 4 person team that will be handling everything from racking to configuration.