What should I consider for re-entering Thailand after staying 120 days on a METV, and which entry method is safer?

I have stayed 120 days in Thailand this year already, based on a METV issued by my home country consulate, Belgium. The METV has expired by now and I am in my home country now.

This year, I have 0 visa exempt entries and 0 land border entries, always entered via BKK airport with the METV and never been questioned. Last year I stayed quite some time on exemptions stamps in Thailand.

I wish to go back for just another 30 days this year and hope to get a visa exemption stamp so I can apply at a school to learn Thai.

Now, based on the reports, BKK is the worst airport to fly into, not having a visa and after staying 120 days this year. I know that finally, "its up to the immigration officer", but what would you do?

Do they refuse entry on the spot or only if you have been warned before?

My next most convenient flight would be Chiang Mai, or take the more safe approach and fly to KUL, then Penang, then take a bus over the border. Then again, I heard reports about particular borders having become more strict. I have never entered Thailand by land. Which land border in Malaysia should I be going for?

I'm aiming for the most convenient way where I won't spend 2 days in planes and buses to get into Thailand.. ;)