Delay should be travel time assuming a pilot is hired who fits a massively Engineered Fuel Scoop and FSD that gives the ship huge jump range regardless of size/mass. At the destination they swap back in your original components that they stowed in the hold.
At 50-60LY/jump it would take roughly 10 minutes to traverse the human bubble, fly from Maia to Sol or from the bubble to Sothis. It also allows long distance transfer to Jaques Station with a suitable time penalty.
Please have a delay, please make it realistic, please don't make it a large chunk of a particular game session.
Putting a sizable delay in for bulk transport of ships allow for the devs at a later date to include features that allow for hired crew members to fly your ships where you want quicker and cheaper. It also allows at a later stage for the devs to include features where you could remotely order your ship crews to change the loadout of your ships to fit a fuel scoop and your engineered FSD held in storage. Just giving us it for free now means we never get this level of customisation and control.