The IB forum does not have a lot of people participating.

As for your questions, the quick answer is "random". We don't know IBs algorithm for upgardes and therefore is difficult to predict. The only thing I can say is that the 'bid' process always has higher cost that getting an offer during online check-in. As for whether you will get an offer at OLCI and for how much... is a total mistery.

My advice is for you to assume that you are going to fly PE and that maybe if you are very lucky you will get an offer to fly J. If you trully want to fly J, book J. IB is not an airline known for amazing customer service or for producing reliable offers.