This produces melt in your mouth types of buns. Naturally, the character of the bread is different. You generally, want to match the character of the bread with the character of the flour. Elizabeth David is one of the few authors on bread, incidentally, who advocates looking for flavour in flours rather than simply high gluten content - a lofty loaf is a good loaf only from certain points of view. Incidentally, buns and the like that I have baked with substantial amounts of pastry flour have had no problem rising to normal respectable levels.
Tolerance means ability to withstand abuse - abuse like overkneading, overfermenting, overanything.
High gluten flours have higher tolerance. This means that you have to be slightly more skillful in using low gluten flours. I would recommend using a yeast dough rather than a sourdough as a starting point if you are going to try to make buns with large amounts of pastry flour. The reason is you have to be very careful not to overferment this sort of dough and it probably easiest to make a straight dough. I have used sourdough and got breads as soft as a kiss.