I can't believe no one has suggested thi yet, but if ATG on your moustache area is the only problem, have you considered not shaving ATG on your moustache.
I've been straight shaving for about 3 months and I will not shave ATG on my moustache. I think for me my moustache has the most densely packed hair, and I also think it angles down steeper than any other part of my face. I can still get the area smooth with just WTG and XTG and streching (I usuall poke my tounge into my lip to get the skin tight).
If you're only on your 3rd shave I would wait until you get more comfortable with the whole process before trying ATG there, and I know several people never go ATG there and still get great shaves.
I've been straight shaving for about 3 months and I will not shave ATG on my moustache. I think for me my moustache has the most densely packed hair, and I also think it angles down steeper than any other part of my face. I can still get the area smooth with just WTG and XTG and streching (I usuall poke my tounge into my lip to get the skin tight).
If you're only on your 3rd shave I would wait until you get more comfortable with the whole process before trying ATG there, and I know several people never go ATG there and still get great shaves.