That's what I've used in the past. Small needle nosed vice grips, modified slightly with small notches near the tip.. It's sort of like orthroscopic surgery, working through that pushrod gallery. Often, old lifters are mushroomed on the end, especially if you are replaceing the cam because of a wiped lobe or two.

Pull, and twist (as well as you can), if you're lucky then the rough cast iron at the bottom of the lifter bore will grind off the slight mushrooming.

If you absolutely can't get them out, the alternative is to pull them up, remove the cam, then push them down into the oil pan. Then remove the oil pan to get them out. So it's worth quite a lot of effort to pull them out upwards.
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'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)