I have created a holder for my DTI which fits the Quick tool change.
I have used this holder for a while https://www.thingiverse.com/thing:2469518 which works perfectly, but placing the DTI on the tool change base is easier for me. I have used the this design as an inspiration.
I don’t use any gcode to level my bed. Instead, I place the DTI approximately 50mm from the left and below, home the Z-axis, zero the DTI, move the DTI 200mm to the other corners which can easily be done with Octopi and keep on leveling until I am happy.
The indicator I use is made by Dasqua and I have bought it from a Dutch site: https://www.hbm-machines.com/producten/dasqua/dasqua-professionele-001-mm-slag-digitale-meetklokken
The shaft is 8mm which is standard so I recon other indicators should work as well. You can contact me if yours does not fit so I can make some tweaks.
Here is the video I have used this indicator in