You could apply for a visa now for your January trip. You have to use it when doing border bounces.
I have been in Thailand nearly ten years and most of that time was tourist visas. I have been pulled aside by immigration twice. They yelled at me, then let me in. You will likely be fine but you are assume certain risks.
You can easily stay 6 months with visa exempt and a border run. You're here to see the sights anyway.
Pattaya city proper may be a little much unless you are into partying
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. Otherwise I would recommend the outskirts. Pattaya is nice enough, I live here now and have been here 5 years. However, Pattaya is in Thailand, it's not really Thailand. Its a town of tourists or expats who like to party. If you want to see real Thailand, I would recommend planning 1 week here and another week there, etc. It may be more expensive but it's a once in a lifetime experience.. Unless you end up living here.