1. Prepare Spinach Whole-Wheat-Bread Stuffing; set aside.
2. Remove giblets and necks from chickens; refrigerate for use in soup another day. Rinse chickens with running cold water and drain well. Spoon some stuffing lightly into neck cavity of each chicken (do not pack stuffing; it expands during cooking). Fold neck skin over stuffing; fasten neck skin to back with skewers. With chickens breast side up, lift wings toward neck, then fold under back of each chicken so they stay in place.
3. Spoon stuffing lightly into body cavities. Close by folding skin lightly over openings; skewer closed. Tie legs and tail of each chicken together.
4. Prepare outdoor covered charcoal grill for barbecuing as manufacturer directs, using indirect-heat method with drip pan (or follow manufacturer's directions if using covered gas or electric grill).
5. In metal-handled small saucepan, on grill, heat butter or margarine, garlic salt, paprika, and pepper until butter melts.
6. Place chickens, 1 inch apart, on grill over drip pan. Brush chickens lightly with some butter mixture. Cover grill and roast about 1 1/4 hours or until chickens are fork-tender, adding briquettes to each side of drip pan at the end of 1 hour as manufacturer directs. (If using meat thermometer, chicken is done when thermometer reaches 175° to 180°F.) During last 15 minutes of roasting time, baste chickens frequently with butter mixture.