The coax jacks I use are made by Johnson --- part numbers 129-0701-301 (horizontal) and 129-0701-201(vertical). Both are available from Digi • Mouse. Johnson 129-0701-201 is shown in the top right photo. Verify the size of your probe sleeve before you order the jacks.
The test pins I use are Vector K24A. The pins are spaced so that the ground sleeve of the probe rests against a ground pin and the tip rests against the signal pin. The Vector pins are available from Digi • Mouse. (bottom right photo)
If it is not possible to design your board with either a coax jack or test pins the loop area can be reduced by coiling the excess ground wire around the probe.