oven-dried tomatoes

Today I am mostly experimenting with oven drying some very large, mature, beautiful tomatoes from my mother-in-law's neighbour's garden. Dona Gloria must be an amazing gardener. Anyway, I will see how my experiment goes, using the oven, since we seem to have lost our super summer, ergo no SUN-drying.
If Lulu at Frittata e Zucchine sees this, do you have any tips for drying tomatoes? Dried tomatoes are unknown in Portugal, strangely, and though a huge favourite it Britain, we obviously don't have the hot summers to make them ourselves.