Match the large table to the sofa, then let the small one be the spare.
Anton Small set is Medium plus Small (70 x 60 cm with 65 x 55 cm). Anton Large set is one Large and two Medium tables (100 x 75 cm with two of 70 x 60 cm). Leo Medium set is 80 cm plus 70 cm rounds; Leo Large set is all three diameters, 95, 80 and 70 cm.
If the sofa is a two-seater, start with Anton Small or Leo Medium. If it is a long three-seater and you host, the large set is the one that stretches along the sofa when pulled apart. Height still follows the sofa seat: see the height guide.