Yup, things have moved out of the early days of solar. Although I don't have 20 years of experience with solar, I spent a year deployed during the Iraq war with a lot of time on my hands for research. So my information for my system was current as of 2003-2004. I chose a system that featured one extra row of cells from the usual 36 to 44. this allows the voltage to go from 175 to 21.5. That is not the open circuit, but normal output. The MPPT controller takes the excess (high voltage) input and with a small loss, inputs it to the battery as an increase in amperage. That would actually be more than the 100% you would get out of your 17.5 VDC system. So that makes it not only a battle of modern controllers, but panels as well.
Bill, the system is from
http://www.amsolar.com/am100.html. Rocky Mtn Ray was an inspiration to my research, especially the mounting process. I wish he was still here to comment.