Spicer's perspective on Percival:

Percival was sort of the kid of the Grail thing. He left home when his mother died on account of it, and everyone died on account of it. He was sort of the vice-president of the Grail. He didn't go off for the Grail but he got to be served from the Grail an he was sort of the innocent. He sounds much better than Galahad to me, who left everybody just sitting there and everything just as bad as it was and went off with the Grail into the big distance up there. [...] Percival's a young kid. He was going to take the Grail. He doesn't quite make the Grail, according to Malory, on account of the fact that once he sleeps with a woman who seduces him in some very complicated way, he can't ever really do the same thing a Galahad, who was completely pure. But he's sort of the best person in the whole Grail story as far as I can see. (61)
From The House that Jack Built: The Collected Lectures of Jack Spicer. Edited by Peter Gizzi.