Rogue Trader focuses on the big ships, miles long, crew in the 10s of thousands but is there any definative answer to how small a ship can be and still travel the warp?
In the Inquisition Wars books by Ian Watson (mid 90s) Inquisitor Draco had a ship about the size of a 747 that housed his team and seemed to need no more than few crew and servitors.
In Eye of Terror (early 2000s) we had a Rogue Trader who owned only his ship and had no crew just a navigator. Again it seemed to be around the size of a 747.
But both are old sources.
Anyone had a definite answer?