By Valentina Za, Giuseppe Fonte and Pamela Barbaglia MILAN (Reuters) -Monte dei Paschi di Siena’s talks with banks set to guarantee its latest share sale will stretch into Wednesday as the underwriters seek reassurances about how much stock they could be left holding, four people with knowledge of the matter said. MPS had scheduled a board meeting on Tuesday to set the terms of an up to 2.5 billion euros ($2.4 billion) share issue, the Tuscan bank’s seventh in 14 years after an 8.2 billion euro bailout in 2017. However, the board had to adjourn its meeting because the group of eight lenders th…