I usually get asked a question related to these kind of mechanics (assuming skilled mechanic) ... "How can one adjust the clearance of 0.08mm with bare hands"?
It took me 2-3 years to understand that these (skilled) Mechanics have been working on ONE KIND of engine since 20-25 years (atleast 5 - 10 years) and usually more than that, Finding the Right Adjustment becomes a piece of cake for them. (Personally tried and tested)
Don't worry about the Tappet Noise. Its perfectly Normal. Valve Clearance in CG125 is adjusted as per the weather. Its incredibly loose in burning hot summer. So if you get them tighter, the noise will become suppressed (almost), but i'll negatively affect the performance of engine.
If the noise is Too Much, and you feel a Loss in Power, or some weired noises while you accelerate, only then it could be a problem.
I also have a 2009 Model CG125 and it has clocked 35k on Odo meter.