Steelhead King brought up an excellent point. The main purpose of fishing with a short float depth is to specifically target fresher fish that are more aggressive. It's a discriminating way to fish if you are picky about what goes on the end of your line.
A couple of other things I want to point out is that:
I don't believe weight would actually scare the fish off. First of all, your offering is drifting ahead of your weight. The fish sees your offering first, not the weight. Secondly, use smaller weights. I generally like to stick with a small float like a Drennan Zeppler #2 or 3, which only require around 1oz of weight to balance. Another option is to use split shots.
Secondly, a long leader under the float does not work too well in shallow faster flowing water from my previous experience. Longer leader allows the offering to float up, missing the intended target zone. It may work better in deeper slots, but I don't know, I generally stick with waters between 3 to 4 feet in depth.
Um, SK, 3/0? We're trying to hook a fish here, not gaff it.