A 12-yeаr-оld with knоwn Type 1 DM presents with glucоse of 490 mg/dL, pH 7.17, bicаrbonаte of 8 mEq/L, and moderate ketonuria. He is tachycardic with a capillary refill of 3 seconds and no hemodynamic instability. What is the CORRECT initial fluid and insulin management according to current DKA guidelines?