If rain is the issue, try to take advantage of overhangs (like the eaves around your house, a covered porch, etc.) and that can score you valuable protection without interfering with the exposure these plants like. My favorite overhangs face E (for my young plants that get only morning sun) and SW (for my adult plants that might be sensitive to rain at certain times of year).
During the winter (our rainy season) I make strategic use of the eaves to protect a few plants that go dormant then and don't like to get soaked during their sleepytime. They might get hit by a few ricochets or whatever, but the real risk is mitigated by a quick 2 or 3 foot shift in location under the eaves.
Your basic N-facing overhang (ours of course would face S) is ideal during the dark days of late fall/early winter because the sun comes more from that direction and less from overhead, so the overhang cuts the water but not the light. Indoors the sunniest window in winter will probably face that direction as well (depending on what kind of obstructions might be outside).
