THere is plenty of load data out on the net for cast loads in the 41. Look up Hodgdon's Reloading page, also Accurate powders, and Alliant.
Myself and my good friend have been working on loads for ours over the past several months. We have found several powders which work very well with a variety of differnt alloys. I would suggest trying out AA-5, 2400, and Unique. If Uniwie is a bit dirty for you I understand that Universal is just about the same, and some folks say the loads can be interchanged. I cannot vouch for this nor do I condone it. There are loads for both powders use them as listed.
THe key thing with cast is fit is king and lube is queen. If your fit is right you can get by with most load with just about any type lube. It's when you get into the upper pressures that the lubes will make or break your loads. Trust me when I say, it ain't no fun cleaning out a barrel full of lead. This said you might as well find you a couple of brass Choreboy scouring pads. Make sure they are brass and not plated steel or satainless. If you find your getting leading, then take a single strand out of the pad and wrap it around your bore brush and it will shuck the lead out pretty quickly.
IF you haven't slugged your bore you should do so and your cylinder mouths as well. You bullets should be .001 or so bigger than your bore and your cylinders should also be the same so that the bullets will actually be squeezing down as they enter the forcing cone. If they are squeezed comeing through the cylinder, then they are already undersized, and you can expect leading to follow. T%his is why a lot of folks shoot the lower BHN bullets as well as they can still bumpo up as then pass throught he cone and start to enguage the rifling.
Anyway, I could go on and on but this link is MUCH easier on the both of us. Read through the listings as well as the book From Ingot to Target. It will shed a LOT of light onto things that will help you out on down the road.
An index to all of the articles/authors and handloading pages on lasc.us
THere is a LOT of info there but you can browse throught he titles and get a great understanding on what your looking for.