By Geoff Grammer / Journal Staff Writer   Carlos Perez watches his drive during a July game against the Las Vegas Aviators. (Adolphe Pierre-Louis/Journal) When Warren Schaeffer fills out his lineup card, he knows he can use a pen at the No. 4 spot pretty much every day. There's not been much more certain for the Albuquerque Isotopes manager than to know he will get production from the clean-up spot as long as he has 31-year-old Carlos Perez available. Entering the weekend, Perez ranked in the top 10 in the Pacific Coast League in home runs (26, fourth), RBIs (71,...