I'ts hard to tell from the photos, but it looks like your wanting to cut into the coolant lines.
The wastegate actuator will be a small tin-can looking thing mounted on the side of the turbo about 30-40mm in diameter. It will have a pushrod coming out of one end and a pipe from the other. The actuator pipe usually feeds from a fitting on the compressor housing.
if when you cut it, you get a hand full of water or oil, you know you have stuffed up.