I built my own Dreadnought, and it is located outside the speaker cabinets (I've never heard of one being placed inside a speaker cabinet). Actually, I've built two Dreadnoughts -- one for my SRS 1.2s and one for my 1Cs. I use the Dreadnought with common ground amp on the 1Cs because I hear a definite improvement in sound reproduction with the Dreadnought vs. the stock SDA interconnect cable. I used Toolfan66's enclosure for one Dreadnought, and I designed and fabricated -- with the help of a machine shop and anodizer -- an enclosure for the second. I've posted pictures of the results in a couple of threads. One has a Toroid of Maryland transformer; the other has an Avel-Lindberg transformer from a group buy pulled together by a member of the Forum.
Integral, critical, essential -- whatever word you like best -- to all the mods on my speakers was Trey of Vr3 Mods. As I've said several times, along with many others, Trey's work is extraordinary, and you should engage him to help you. You won't be disappointed.
Good luck on your work on your speakers. There many knowledgeable, great folks on this Forum who will give you guidance throughout. Darqueknight's work and documentation is extraordinary!