What probe/tip to use to clip into a PCB test point?
for Probe tip, slightly bigger than needed:    


 expolre here: https://www.digikey.com/products/en/test-and-measurement/test-points/616  



If space is a problem, then have a testpoint and connect a small wire. Be careful with the wires and not to pull it accidentally, pulling off the test point itself from the PCB.  Put glue to secure the wires to the PCB first.