OK, I see what was quoted about TCS but aren't those rules mainly for torment play, not your adventure class ship or a warship found and brought back to life? for instance someone mentioned tanks.
"Three main reversions of the M1 Abrams have been deployed, the M1, M1A1, and M1A2, incorporating improved armament, protection, and electronics. These improvements and other upgrades to in-service tanks have allowed this long-serving vehicle to remain in front-line service. In addition, development for the improved M1A3 version has been known since 2009.
In July 1973 a trip to the United Kingdom, in order to witness the progress of British developed Chobham special armor, was made by representatives from Chrysler and General Motors escorted by the personnel from the Ballistic Research Laboratory and the XM1 Project Manager, Major General Robert J. Baer.[64] They observed the manufacturing processes required for the production of this special armor and saw a proposed design for a new British vehicle utilizing this special armor. Both contractors reevaluated their proposed armor configurations based upon the newly obtained data. This led to major changes in the General Motors XM1. The most prominent of which is the turret front changing from vertical to sloped armor. The Chrysler XM1 on the other hand retained its basic shape although a number of changes were made. The Ballistic Research Laboratory had to develop new special armor combinations in order to accommodate the changes made by the contractors.[65]
For the base model M1 Abrams, Steven J. Zaloga gives a frontal armor estimate of 350 mm vs armor-piercing fin-stabilized discarding-sabot (APFSDS) and 700 mm vs high-explosive anti-tank warhead (HEAT) in M1 Abrams Main Battle Tank 1982–1992 (1993).[10] In M1 Abrams vs T-72 Ural (2009), he uses Soviet estimates of 470 mm vs APFSDS and 650 mm vs HEAT for the base model Abrams. He also gives the Soviet estimates for the M1A1, 600 mm vs APFSDS, and 700 mm vs HEAT.[9]
Armor protection was improved by implementing a new special armor incorporating depleted uranium. This was introduced into the M1A1 production starting October 1988. This new armor increased effective armor particularly against kinetic energy rounds[66] but at the expense of adding considerable weight to the tank, as depleted uranium is 1.7 times more dense than lead.[67] The first M1A1 tanks to receive this upgrade were tanks stationed in Germany. US-based tank battalions participating in Operation Desert Storm received an emergency program to upgrade their tanks with depleted uranium armor immediately before the onset of the campaign. M1A2 tanks uniformly incorporate depleted uranium armor, and all M1A1 tanks in active service have been upgraded to this standard as well.[68] This variant was designated as the M1A1HA (HA for Heavy Armor).[8]
For the M1A1HA, Zaloga gives a frontal armor estimate of 600 mm vs APFSDS and 1300 mm vs HEAT in M1 Abrams Main Battle Tank 1982–1992, nearly double the original protection of the Abrams.[8] In M1 Abrams vs T-72 Ural, he uses different estimates of 600 mm vs APFSDS and 700 mm vs HEAT for the front hull and 800 mm vs APFSDS and 1300 mm vs HEAT for the front of the turret.[9]
The Abrams may also be fitted with reactive armor over the track skirts if needed (as in the Tank Urban Survival Kit) and slat armor over the rear of the tank and rear fuel cells to protect against ATGMs. Protection against spalling is provided by a Kevlar liner." copied from https://en.wikipedia.org/wiki/M1_Abrams
So in the end the M1 was brought back striped down and rebuilt at least three reversion times and the "Armor" redesigned and reinstalled as well, So in traveller nothing is mentioned in the MGT1 core or HG about not being able to do such to spaceships and referring to TCS is RAW but mainly for torment restrictions. We see tones of modifications / updates in most of our manufactured items in "real world". So I can see a restriction of the first "prototype" spacecraft of its new class being on the costly side but once done it shouldn't be much more than it would cost to build it that way in the first place. otherwise we would never have hot rods, ironclad boats, etc... even in computers if it dies you take whats left and rebuild better and faster, new processors, memory, hard drives etc... i.e. "where theirs a will theirs a way or there is more than one way to skin a cat"
If you go the requirement of same size or smaller because of the shell couldn't you infringe on the storage and rearrange internal walls (not support per-say like in a house) and install two or more smaller units in place of the larger unit similar to adding a locomotive to a train to pull more in tandem. In a way its like a team in tog of war. A lot of people pull on the rope. As the other people pull their load and it starts moving, yours gets easier and you can ease off. Just as long as they are all pulling in the same directions.
that's my 2cr worth,
