Several BP revolver questions?

I have several questions that have come up and I need some help. I have a 2nd generation Colt 1st Dragoon that I just purchased. I have three 58 Pietta Remingtons that shoot better than anything I have in the safe as far as accuracy but this Colt with the front sight is different. Its front post is very short and I want to keep it as original as possible. Do I just aim low? Also Dixie and CCI no11 caps are too small for the nipples and Remington 11s have to be pushed further on with half of a wooden clothes pin which gives me enough leverage and still allows me to be as safe as I can while doing it. Is there a better cap alternative in regards to fitting this gun? And can I use replacement nipples that would take a cap better and still be the right length for this Colt?

Move the target farther away and try a different batch of rem # 11s.:)

its normal for colts to shoot high. Which means you need to aim low. Especially at around 25 yards. This is so that when your aiming at targets at about 50 yards or more you will be right on. Takes a little at getting used too. i shoot better with them than i do with my auto loaders