It depends on what you want, really, and the length of your growing season. Once mature, Piilu will bloom double, but only on old wood, so this is one reason to leave some/all old wood (pruning type 2). It does grow quickly, so if cut back as a type 3, it should still bloom nicely, just a few weeks later and probably more floriferously.

I prune most of my 2's as 3's every other year or two to keep them in bounds. Doesn't hurt them either way.

The growing season here, is rather long, compared to much of the US.