PROBE RADIUS COMPENSATION

Hi everyone,I’m currently working on calibrating my 5-axis CNC milling machine, and I’ve encountered a few challenges. I need to accurately probe multiple points on a workpiece (such as a rectangular block or sphere) to align the machine and compensate for any errors. The goal is to determine the exact machine positions relative to the theoretical workpiece coordinates.For this, I’ve been debating whether to buy a commercial probing tool (e.g., Renishaw or Blum) or design and build my own probing tool. Here’s what I’ve been considering:
 

• When the B-axis is tilted, compensating for the probe radius can get tricky. For example, if I’m probing a side of a rectangular block, I have to account for offsets in both X and Z (or other axes, depending on the tilt). This makes me wonder if switching to a spherical calibration disk might simplify things, as the sphere has constant radius compensation regardless of tilt.
• I’ve designed a potential DIY probe where the tool tip is connected to 24V, and the workpiece (or calibration disk) is connected to the CNC controller’s input port. When contact is made, the circuit closes, and the signal is detected. This seems similar to how commercial probes work but is much simpler.

my Questions are : 
1- if i switched to spherical shape instead of rectangular one will it simplify the calibration process, especially when compensating for B-axis tilt?
2- is there is a predefined probe radius compensation in linuxcnc which i can use and it take considaration a titled workpiece
3- For a DIY probe using the method described above (24V signal on contact), will this provide sufficient accuracy and reliability for calibration purposes or should I invest in a commercial probe for the long term ?