Captain reports being blinded by the ramp flood lights during parking at an express gate with a wet ramp. The parking maneuver is complicated by non-standard marshaling signals.

Narrative

Taxiing into the gate in CLT on this morning; I identified what I feel is a definite safety hazard. Finding the gate during night (dark) conditions in CLT can be a challenge; but at night during periods of rain it is very nearly impossible to do safely. There are several factors that cause this: 1. The ramp is wet and glossy; and the lines that are painted are not reflective. They do not stand out at all when the ramp is wet. 2. The flood lamps are rigged to shine on the parking spots at exactly eye level to the crew trying to park the airplane. The effect this has is to make a marshaler nearly disappear in the super nova white glare of the construction lamps we use to light to parking spots. 3. Those same lamps' light reflects off of the wet ramp; making it even more impossible to discern where the actual parking spot might be. 4. The marshaling provided by our ramp staff is of uneven quality at best. On this particular morning; I never saw the taxi line until I was on top of it. The marshaler used non-standard hand signals to indicate where the parking spot was. Of course; my night vision was completely shot by staring into the huge construction lamps. I understand that CLT is in a perpetual state of construction. That being said; this is no excuse to have such a dangerous parking set up. Repaint the lines; reconfigure the lights with some pilot input and have the ramp staff retrained on proper marshaling procedures.