Four OCS players are in the top 10 after two rounds, with Alexander Hall in eighth (148) and Lemon tied for 10th at 151.
Idabel's Stauter in front
As winds picked up and legs grew tired in the second round of the day, many players saw their scores go up, but Idabel's Nick Stauter was able to fight off the trend.
Stauter shot 68, five shots better than anyone else in the afternoon round, to give him a 138 total and four-stroke lead over Purser and Okmulgee's Jackson Hess, each at 142.
Hess opened with a 68, matching Stauter for the low rounds of the day. OCS' Schaefer was the only other player to break 70.
Paced by Stauter, Idabel is in third place at 606, with Pauls Valley fourth at 630.