The DD jacket is too wide at the shoulders and too roomy in the chest; I also don't care for the excessive leather below the zipper end (although that may be consistent with the original).
Just save the DD for layering. The extra layers will fill out the chest area and often the extra padding effectively "lifts" the jacket slightly as well. You now have a Buco for cold and warmer weather!
El, if you can have a picture of the DD zipped, that would be cool.
I had been thinking of the RMC J100 for a while, but then DD came alive and I gave it a try. So far I am very glad with the purchase because the cutting distinguishes itself from any other cafe racers. If you look from a distance, the RMC J100 just looks like any ordinary cafe racer jackets with its shorter length and square shoulders, a bit like the Vanson Comet, which is, by the way, more than half of the price. I also bet that nobody can distinguish between the horse and the steer hide if they don't look at the tag, nor, nobody would ever know it has a Buco tag in there. But that is just my own assessment (sorry about that, RMC fan boys!).
I'm scared my jacket might get butchered, so thats holding me back. I'll be wearing the DD one with layers - For now
That jacket still looks brand new! Give it some time to break in and settle before you do anything to it.
Leather is forgiving when it comes to sizing, once it moulds to you it will look much better.