Dear mystic,
It is useless to ask people here if the measuring instruments that you suggest are accurate. Even if someone owned one identical to what you post, yours may be different; it is not the same tool. Nobody can sit in a chair at a keyboard and predict that a low cost measuring instrument is accurate to a degree acceptable for your use. You need to buy one and have it checked. Another way to check accuracy that is good enough for your stated purpose is to compare measurements done with a tool that is known to be accurate. That should be a tool that has been checked against a standard, not a tool that someone bought for a lot of money 5 years ago.
Can you or anyone tell me if my 15 dollar tire gauge is accurate? What if the identical tire gauge is for sale on Amazon; does that make a difference? No, I didn’t think so.
PS, a good way to check cam lobe lift is with a dial indicator with the cam mounted in a metal cutting lathe. Harbor Freight also sells inexpensive dial indicators. Don’t ask me if they are accurate. I own one and don’t know.