matching speaker to room size?

I have a 14 x 16 room with 9 ft ceilings and looking for new speakers. Presenlty using large old Ohm C2 bookshelfs. Listen to broad range from modern and classic jazz (piano, guitar, horns and vocals) to electric blues, tons of female singers, Hawaiian acoustic and fingerstyle guitar, classic rock and even some classical and newgrass like Nickel Creek and Alison Krauss. The one dealer in town suggeted stand mount monitors like Totem One, JM Focal 1007S and similar. I have been more interested in floorstanders like Gallo 3.1, Dali Mentor 6 or Helicon 4. He is saying this will give me too much bass? Is there a way to compute good match from room dimensions? I listen at low to high levels depending on time...Saturday mid-day vs. 11 at night. I have heard all these speakers, not necessarily side by side, trying to make a call but not sure which type to go with so I cant even proceed to which individual speaker to purchase. BTW, I dont have the optoin of bringing any of these home...most were heard on the US Mainland not in Hawaii.