The O.P. actually said lower speed and more thrust was the desired effect...

Anyway, prop selection is heavily affected by the airframe and the personal preference of the pilot.

In some cases (I don't think it applies here, but I've personally done it), you can actually pick up airspeed by going down in pitch. This is most common on draggy airframes, and with engines that are being slightly overloaded by the larger pitch prop. Our engines aren't linear, and they don't always turn the same RPM. A prop with the same diameter and less pitch will turn at a higher RPM. That sometimes more than makes up for the loss of pitch, so you have to try it, and don't assume that adding pitch always speeds up the plane and reducing pitch always slows it down.