Here's a quick pictorial tutorial about how I combined left over bits from the new Furioso kit with an Assault on Black Reach Dreadnought to make a Death Company Dreadnought. You can use this method to make any of the variants, but I already have a Furioso and I used the new kit to make the Librarian version (pics coming soon).
First off I used the razor saw to cut along the top of the front piece of the AOBR dreadnought.
Next I cut the front off. I could only go so far with the razor saw, then had to go from the bottom. Its a little tricky, but I cleaned things up with the exacto knife after.
Sorry this one is blurry, but here I'm cutting from the bottom trying to align the angles with the other front.
Here's what I'm left with. I had to make sure the little bits on either side were left in place. There's also a bit that goes in the middle at the top that I had to preserve.
Next off I worked on the left shin armour. This had to be carved off and prepared for the replacement one from the Furioso kit.
Here's what it looks like now:
I'll be sure to post pictures of it when I paint it up.