how to change the default positioning of modal in bootstrap?

Answer 1

I get a better result setting this class:

.modal-dialog {
  position: absolute;
  top: 50px;
  right: 100px;
  bottom: 0;
  left: 0;
  z-index: 10040;
  overflow: auto;
  overflow-y: auto;
}

With bootstrap 3.3.7.

(all credits to msnfreaky for the idea...)