Okay, this here is a blatant kitbash, which in-universe is termed as "Ugly". Corellian Half-Hull? Half-Freighter? Half-Bad? Half-Measure?
In my SWU/SWM, Only 1 or 2 Outlaw groups are making these.
I'll be making stats for Stock (Space: 5, Atmosphere: 295; 850 kmh) & Modified (Space: 9, Atmosphere: 400; 1,150 kmh) YT-1350 & YT-1355 light freighters.
i *might* do the Half-Hull Ugly later...

Space: 5
Atmosphere: 500;850kmh
it hurts a bit, every time i see random numbers like this, compounding WEG Errors, instead of fitting the WEG Speed Charts in the rules section...
http://d6holocron.com/wiki/index.php/Expanded_Speed_Chart
Space: 5, Atmosphere: 295; 850 kmh
Space: 6, Atmosphere: 330; 950 kmh
Space: 7, Atmosphere: 350; 1,000 kmh
Space: 8, Atmosphere: 365; 1,050 kmh
Space: 9, Atmosphere: 400; 1,150 kmh
The Copy+Paste error "Space: 4, Atmosphere: 480; 800 kmh" is everywhere...

I prefer the Frank Bonura correction of Length: 37.38 meters over the revised Canon & Legends Length: 34.75 meters.
Length: 26.7m belongs in the past.
Let the past die. Kill it, if you have to.
((though, tbf, i do have Czerka & outlaw shipwrights making Length: 26.7m Fake/Knockoff YT-1300s...))

length conversion chart they use over at the Star Wars Deckplans Alliance:
https://rancorpit.com/forums/viewtopic.php?p=184610#184610
If a freighter's WEG length is < 53.4 meters long: 140%
If a freighter's WEG length is 53.5 to 106.7 meters long: 120%
If a freighter's WEG length is 106.8 to 213.5 meters long: 110%
If a freighter's WEG length is >= 213.6 meters long: No change
So, take the listed WEG length of a ship, compare that to the above list, then multiply accordingly.

For example, the 26.7 meters listed for a YT-1300 falls into the 140% range, so multiply 26.7 by 1.4 to get 37.38 meters.

Obviously most freighters that characters will be using fall into the 140% range.

That said, i do think this ship is a neat idea.

Okay, this here is a blatant kitbash, which in-universe is termed as "Ugly". Corellian Half-Hull? Half-Freighter? Half-Bad? Half-Measure?
In my SWU/SWM, Only 1 or 2 Outlaw groups are making these.
I'll be making stats for Stock (Space: 5, Atmosphere: 295; 850 kmh) & Modified (Space: 9, Atmosphere: 400; 1,150 kmh) YT-1350 & YT-1355 light freighters.
i *might* do the Half-Hull Ugly later...

Space: 5
Atmosphere: 500;850kmh
it hurts a bit, every time i see random numbers like this, compounding WEG Errors, instead of fitting the WEG Speed Charts in the rules section...
http://d6holocron.com/wiki/index.php/Expanded_Speed_Chart
Space: 5, Atmosphere: 295; 850 kmh
Space: 6, Atmosphere: 330; 950 kmh
Space: 7, Atmosphere: 350; 1,000 kmh
Space: 8, Atmosphere: 365; 1,050 kmh
Space: 9, Atmosphere: 400; 1,150 kmh
The Copy+Paste error "Space: 4, Atmosphere: 480; 800 kmh" is everywhere...

Sorry, delete/ignore 2nd post

I always just make up my own Space/Atmosphere speeds, as I feel it depends very much on the aerodynamics' of the vessel.
I took it as the reason why Starships are incredibly slow in atmosphere (because they're really not shaped for it), and you can get speeders which are faster (as they are designed for it).
Big blocky transports will be fairly slow in the atmosphere, whereas some fighters will perform faster than their space speed would indicate they should.

(and yes I know that in-universe shields are supposed to create an aerodynamic shape around ships to help overcome them looking like flying bricks)

Starships using repulsorlift engines for atmosphere play into it too. They "can" use their ion engines in atmosphere, but this is frowned upon by people living on the planet, lol (Original Thrawn Trilogy)