Do you definitely have compression in all cylinders (given all the work that's been done and the damage before you started)
Bare in mind the 1.3 multijet runs freakishly cold, I drove mine with no coolant for 20 miles in cold weather with no ill effects, And one year in snow, I tried to warm some water on the engine to defrost the frozen wipers only to find there was no hear coming off anything I could access under the bonnet.
You could likely get away with more than 30 seconds of run time.
Congrats on the rebuild looks like you've done a lot of work to get it to this stage.
Bare in mind the 1.3 multijet runs freakishly cold, I drove mine with no coolant for 20 miles in cold weather with no ill effects, And one year in snow, I tried to warm some water on the engine to defrost the frozen wipers only to find there was no hear coming off anything I could access under the bonnet.
You could likely get away with more than 30 seconds of run time.
Congrats on the rebuild looks like you've done a lot of work to get it to this stage.