I have an Avancargas Anchu, S.L. (Spanish) double barrel shotgun with 30 1/2" steel barrels, straight stocked and according to the proof marks the shotgun was built between 1929 and 1932. Knocking a bird out of the air with one of these does put the hunt back in Hunting!!!!
The only thing with a double is you CANNOT be or get distracted while loading. I place the ram rod in the barrel I'm not loading in order to give myself a reference point and I always follow the exact same procedure while loading, the shotgun is always in the same orientation so as not to switch them around.
My wooden ramrod is marked with an ‘unloaded’ notch and a 'loaded' notch so I can readily tell if the barrel has a load in it or not, heck with those fiberglass or other composite ramrods that can't be notched or marked in some way because that is the only real way you can tell if its loaded by placing the ramrod down the barrel and measuring where the end of the ramrod is in conjuction to the breach end of the barrel.
I clean up with hot soapy water then spray liberal amounts of WD40 to displace the water, wipe then oil.
I can spend all day shooting skeeters for a whole lot less then a breechloader!!!
All the best