There shouldn’t be any big difference between weekends in January. There are no CR holidays. The US holiday of MLK day might bring a few more gringos with the extra day off, but probably not enough to notice. First week to avoid is Holy Week in April.
SL is a good choice for a first timer. There will be guys at the bar that can give you advice. Chica reports vary, but I’m sure enough will probably be around. If not, there are other venues.
In any case you should get out and check the other venues in town. You can walk to Castillo, Taormina, Little Havana, Del Rey, and Monicas. Totally safe walking during the day. Although I follow the advice of most on the forum and taxi or uber at night.
Everyone has a different atmosphere and vibe with which they are most comfortable. Reading comments can help, Harddrive posted a good summary of hotels recently
viewtopic.php?f=4&t=53790 about the fourth post down. But you don’t really understand until you visit a place in person. It will help plan future trips.