Liszt didn't notate the Consolation for 3 pedals, of course (the sostenuto hadn't been invented at the time!), so you can omit that one on grounds of authenticity. Otherwise there are two ways to use three pedals at once - I've done both:
1 Put leather pedal covers on the pedals (goodness only knows where you buy these, a friend owns a set) and this will give the extra width to the pedals that allows you to rock one foot sideways on two pedals. It's certainly easier if the pedals are close together, as on American Steinways.
2 Use heel and toe, which is agony as it means bending your leg into a most unnatural position.