Basing Conundrums

Happily tucking into my first shipment of painted Eureka Miniatures 18mm Seven Years War figures from Old Guard Painters, and I realized I cannot fit four cavalry breast on a 1.5" base, but the infantry fit great. So should I stick with 1.5" bases, or upsize to 45mm bases? I think four abreast would look a little more solid, but 45mm square bases start to get big.

Pictured below are the Prussian von Blanckensee dragoons and a base of the Austrian Kollowrat infantry. Conundrum not solved...