If you look at the page for either of the SpinPonchos (found here) there is a link to a PDF that is called:
Click here to download the SpinPoncho User Guide (Adobe PDF)
Once you click on the PDF you will find that it says not to pitch the SpinPoncho in an A-frame configuration. It says the plane of the hood needs to be...well...a plane, in other words, flat. It recommends a lean-to type pitch. That seems less useful to me. Perhaps it's just because the material is spinnaker, but the Golite pictures of their poncho also show a lean-to.