As a repairman who fixes logic boards almost every day (including shorts, of course), here's the advice:
First of all, it doesn't matter at all where exactly you inject the voltage on the same line, as long as you're sure it's the correct line, you're good (a proof of which is a fixed 0.00V on the line). Can be a resistor, a cap, an SMD chip, whatever, all the same, they're all connected to each other. There is very little chance that you will inject the voltage exactly into the component which is shorted, but I only heard stories of that, never happened to me in several years of experience.
Second of all, start with injecting something like 1V with 1A limit, if it immediately draws max current and pulls power supply voltage down, you may want to increase current limit to 1.5A or 2A. If the current is not hitting the ceiling, you can turn the voltage up to 2V. After that while the power is still applied and the short is wasting precious milliamps, you can start touching the board everywhere in an attempt to find the warm spot (as you probably know if you know that you should inject voltage). If nothing shows up, add a little more voltage and current. You don't want to send 3A right away, you may damage traces which are not designed to carry high current. They can take an amp or two for 10-15 seconds with no harm, so basically apply power, touch-touch-touch-touch, shut down, wait 5 sec, apply for 10-15 sec again. The more current it pulls, the shorter time you apply power. If it's some 3Amps, it's better to apply it for 5 seconds max with 5 seconds pause. Apply - touch-touch-touch in some area, turn off. If still nothing shows up, you can actually touch it with lips, sometimes some thick beefy caps don't get very hot and you can't find them immediately, it's fine (but usually you can immediately tell and it's really hot). You'll find warmer place. Sometimes you can also kinda think that something is warm, but it's your brain tricking you, and you have only probably warmed some capacitor up by holding fingers on it.