welcome to the forums
and good4u trying to sort ALL of these issues, PRIOR to buying.
i see your questions (in these 2 threads) lumped into 3 general categories...
1. trailer specs, build issues, structural differences and so on...
2. w/d in regard to hitches, calculating vs measuring tongue weight and how that all relates to tv selection.
3. tv ratings, matching tv to trailer and meaningful modifications to the tv that may enhance real world towing.
the tangential issue related to #1 is "what size/floorplan stream do i need"
the tangential issues related to #2 are many and will eventually involve SELECTION of a hitch apparatus.
the tangential issues related to #3 are also many but for now focus on axles, springs and supporting payload.
is that a reasonable summary?
for now this post focuses on #1 with a tiny bit on #2.
#3 and most of #2 will go into your OTHER thread.
u have correctly concluded that the floor plan graphics are improperly scaled.
the LISTED lengths are correct the 27 is longer than the 28.
a/s is well know for doing this, for example classic 30s and 31s are exactly the same length.
they differ by floor plan and the 31/30 tag was a simple way to make that distinction.
the actual FRAMES on 27s and 28s are different.
the 27 as a rear door model has different outriggers and structure around the steps/door.
the 28s as a front door model has specific outriggers and support around the door/step location.
they MAY be other differences, like # of cross braces, outriggers and placement of the axle cut outs.
a/s doesn't make the frames, leland does,
and since heavy things are in different locations it is not UNreasonable to assume frames differ.
the gvwr are diffent, so u might also ask IF the axle ratings are different for the 27 vs 28.
i had a similar set of questions back in 05 when sorting out an order,
and only cleared things up, after a few email exchanges with a/s tech/customer support.
the dealer also hounded them about these questions, since i was unwilling to BUY without the details.
LUCKILY 4 me, no one responding here (trying to help) suggested a DIFFERENT SIZED UNIT.
knowing exactly what size/floor plan i wanted was a done deal, so suggesting smaller would not have been helpful.
the printed materials, the website and the actual SPECS for any given unit or year (especially new) don't always MATCH UP.
often the factory web site differs from the dealer pamphlets.
1. contact tech support with your questions about frame/tongue issues
, they will tell u the differences between a 28 and 27.
ok now a few notes on #2 above, the w/d issue.
a/s has 4 a long time UNDER estimated tongue weight, leaving out spare tires, lpgas and options.
recently they've started including spare tires and appear to be TRYING to improve published estimates.
still the only real way to know is weighing the tongue, loaded, gased, watered and so on...
steverino' report doesn't mention IF w/d was engaged, and is indirectly estimating tongue weight (that's not a bad thing)
i understand U are interpolating that data to arrive at a higher real tongue weight.
that's fine except the notion of 1/3-1/3-1/3 or 2/3-1/3 is NOT based in reality.
it may have been at one time (i doubt it) when single axle, short trailers and long sloppy sedans were the norm...
the goal of w/d is to RESTORE steering axle loads NOT distribute the tongue equally over all axles.
we can dig further into this later but for now, don't assume a 27-28 has a 12-1300 lb tongue.