Sam, if I may ask you one more question: I know what the A, B, C, and M designations stand for, but what is the difference between a -25 and -50 block? Thay both have 66 pins per column. The only difference I can see is the -25 is electrically connected between columns 1 and 2, and 3 and 4 but the first two columns are electrically isolated from the last two. In the -50, all the columns are electrically connected.
