I've never fished Horsetooth.. but I know there is a TON of smallish bass in there... I'd say try a Tube!
I like Gitzit tubes from Walmart
I know there are plenty of other good tubes out there i just have done good with Gitzit... i bought this assorted pack from Walmart:
Really though your options are almost unlimited!! Find a lure you like to use and stick to it... Confidence is key!!