I'll manage, thanks.  Ton of potential but decades of sitting.

DDidn’t the imperial get the hemi in 54?

Chrysler introduced the Hemi at 331" in 1951 and of course it was shared with Imperial.   DeSoto received a smaller Hemi in '52 and Dodge got a 241" Hemi in '53.
Chrysler enlarged the Hemi to 354" in '56 and then 392" for '57 and '58.  That ended the first generation.
DeSoto and Dodge both had their last Hemis in '57.

First, the common mistake is to spell it like the well known chewing tobacco, Bull Durham.  But the coachbuilder in Rosemont, PA was under the family name DERHAM.
I found ONE of the scripts in the glovebox.  Other missing if someone can help.  The photo is from the WWW.

That shouldn't be hard to cast I would think.

Derham throughout their decades of coachbuilding had one iconic customization and that was padded tops (most leather, some nylon) with a closed/covered quarter window and a formal small backglass.  Variations per body style and customer of course.  They built custom jobs and prototypes as well, notably under contract as the "house customizer" - we'll call it -  for Chrysler Corp with that relationship ending in '55.  
A second common change was the addition of a division glass partition, the hallmark of limousines throughout the auto industry..

Still early in my research having discovered this car a couple months ago so can only describe that one '55 Impl formal sedan was built for Chrysler CEO KT Keller with division glass, padded top and medium sized formal back glass.   And one, my car, with the division glass, no padded top and production sedan backglass.  Keller's believed to be black.  Mine is Crown Imperial Blue (a Model 70 limousine color).  There is a hint in the car's included file that this car was part of the Eisenhower administration but unable to verify so far.
I can not find anything regarding further '55 Formal Sedan creation from Derham.

Thanks.  My dream shop constructed first before building the new house.  Priorities ya know!
In the distance is my first '55 Imperial, a survivor Newport.

Love it!

Nice.  That is an outstanding car!

That is the '55 Imperial parade phaeton built on special order by Derham for Eisenhower's use during his administration.  It is in the carriage house at his Gettysburg farm and is owned by the National Park Service.  It is on the Model C70 long wheelbase limousine chassis.   
My car is a Model C69 Formal sedan, standard wheelbase which for 1955 only was four inches longer than the Newport two doors allowing room for the division glass installation.

Age/health limitations; slow minor progress.

I'm a big believer in not ripping a car apart.  Small incremental improvement so you still have a complete car but it is a little better than the week before.

Cool stuff.  Is that a factory press package you have there?

At the risk of sounding stupid, what is "flash chrome plating" vs traditional chrome?

Factory press pkg, yes.  Mine, no.  Pages posted on FB recently.   The cover.

Generally we talk about chrome plating as the triple process taking bare metal and then 1.copper, 2.nickel and 3.chrome.   As you know, in triple plating, the nickel is what you are actually looking at and the chromium is a clear protective coating.   So, flash plating is the application of the chromium over an already polished metal such as stainless steel side trim or wheel covers.   
There are probably many more applications of this than I'm aware of.   I'm guessing some of this started because the quality of stainless steel in the auto industry was cut during the Korean War effort by the government.   For example I owned a very low mileage '53 Hudson in Chicago in the late '70s.  The chemicals on N. Illinois winter streets quite badly etched the side trims and wheelcovers of that car.  Flash plating would have protected them but Hudson Motors could not afford the extra process.  NOS trim was installed when I located a set.

Thank you.  I just learned something.