@Duvel You've probably found a solution by now, but on the off-chance that you haven't, I've noticed that the empanada dough I've developed over time (I wanted a flexible crust, rather than a flaky one) doesn't shrink or expand, and it holds its shape (i.e. the crimping at the edge changes very little, even though it's not in a mould that would support it during baking), once baked. I usually use half a kilo of flour at a time, but this recipe may be multiplied and divided without any adjustments to the ratios.
In a bowl, combine 500g flour and a teaspoon of salt;
In something with a pouring lip, combine 250ml water and 60ml oil
Add liquids to dry ingredients, and knead until smooth.
Ideally, let rest in a cool area or the refriegerator, but I tend to be impatient and use it immediately, and the results are still fine.
I vary the amount of salt depending on the empanada filling I'm using, and choose the flour and oil on the same basis; depending on the flour you're using, you may need more or less water.
I usually bake empanadas in a 200C oven (with convection) for a quarter of an hour; time and temperature may need some adjustment for meat pies cooked in a mould, particularly if the filling is uncooked.
ETA I think that any dough that fits yor requirements would need to contain a decent amount of fat (to minimize/avoid shrinkage: water/water-based liquids evaporate), no leavening (to avoid puffing up), and be relatively firm (so it keeps its shape).
