I dropped mine to 400 tons to match canon size. Still TL16 and less expensive than the one in High Guard. MCr11 less expensive than the one posted here, too. Winning!
My thoughts on the build presented, in no particular order.
I was able to use the space saved by cutting 10% of the fuel to have staterooms for everyone. On a ship that could be on the move for months, that seems pretty important. I don't believe cabin space would cut it.
I have a pair of sandcasters for defense, so the ship still needs to run from danger, but it might be able to defend itself. I also have M6 rather than M5, so it can run faster.
I have the full military crew, whereas this design cuts the medic and mechanic. I believe in running full crews as defined in the book where possible. Unlike Mongoose, I follow the crewing rules.
This ship has no small craft of its own, but I added a 4-ton runabout of my own design.
No batteries for jump? That's some wasted space, in my opinion.
A light hull on a military vessel? Seems contraindicated. I went with standard.
I don't have offensive weapons, so went with Virtual Gunner/0 rather than /1. Saved MCr4.