I'm another fan of the 7 liter bullet feeder/waterer. Some prefer homemade PVC pipe water "tanks" with nipple type outlets, but while they can be built with much greater capacity, I'm not so good at remembering to refill one. The bullet type is translucent to let you see what's left in it at a glance.
And, on the advice of more knowledgable pigeon guys, I've found that switching from a pelletized diet to one that is primarily grain dries/tightens up the birds' droppings considerably. Unlike the plaster of pelletized feed's pigeon pies, grain droppings mostly roll off the perches.
Because I'm too lazy to offer a ballanced grain and legume diet to insure they get all they need, like the big kids do, I provide a bullet feeder of high protien "pigeon" or "laying" pellets the birds sometimes use to suppliment their rice (cause it's handy/free here, but corn works about the same) diet. Think you'll find, as I have, that offered both the birds much prefer whole grains, and you'll be doing much less scraping.
If I wan't concerned about maximizing new bird production, I'd probably not bother feeding anything but a grain of some type.