|so now I really need to buy that voltmeter right...
sounds like you know the answer already
Dont worry..pencil mods are cake. Just make sure you un-plug the PSU and give the mobo a rest for a couple minutes, to let any charge in the caps dissipate. Shade away, start up then measure...rinse and repeat until you got the desired amount of droop you are looking for. I would encourage you to only lower the resistance enough to 'fortify' the vcore at the OC you are currently working on. Trimming the droop all the way down to .00v is easily done, but adds extra strain on the caps and Vreg's. To help with the strain..I 'sinked all my VR's around my CPU and added another 40mm to the mix.
*kinda off topic-
Since I have done the mod on my P5B-dlx, I have done a suicide run to 500mhz..which is near impossible with this OCZ crap..anyways, I made it to 482mhz, 7x for 3.8ghz..and with only 1.51vcore! Thats .8v less than before the vdroop mod
! The highest I went,I was able to hit windows @ 4ghz with only 1.61vcore, compared to 1.71vcore before. Quite an improvement I would say..an I didnt even need to solder.