Having had issues in removing an NRV from a primus 7 (see this thread) I managed to pick up a couple of extra long (7 1/2 inches) NRV tools which I have modified as shown below with some 'Delrin' rod. I find this with 'presscall's' tip about holding the tool in a vice and rotating the stove prevents (so far) any camming off the NRV The rod acts as a spacer to prevent wobble and slipping off the NRV - I may rack out / add spacers to the two sections of Delrin to give a more even bearing in the pump tube.
Looks good. Keeping the NRV tool in the centre of the pump tube (top and bottom ) makes the successful NRV removal much easier.