I've revised where to cut the fuselage after feedback and I have made the rear fuselage a one piece hollow cast part.
Gently scribe along panel line, then cut through plastic.
Final Revision - One Piece Hollow Rear Fuselage
After cutting and sanding KH fuselage at engraved panel line and sanding resin rear fuselage where it mates, tape resin rear fuselage to the KH fuselage. Align and tack Super Glue at points indicated, when satisfied with alignment continue gluing. Reinforce joint with styrene strips from inside. Rescribe panel line.
NOTE: If you have a set with the longer fuselage parts, you can keep it long, but be advised that if the seam is not lined up right, it will be more obvious closer to the middle of the spine and sanding would remove more detail. Near the vertical stabilizer fillet, it would not be as obvious. The cut line further aft is to allow for more KH fuselage above and behind the wing. It makes for a less flimsy assembly and less twist to the fuselage.
Using .080" drill bit, round file or hobby knife blade, make sure holes for horizontal stabilizers are open in resin rear fuselage parts.
Suggested method for gluing the resin tail to fuselage is to glue one side first. On a flat and level work surface align the parts and glue with cyanoacrylate (thin super glue). Reinforce the inside joint with styrene strip.
Glue KH cockpit and nose gear compartment box. Now glue other KH fuselage side. Dry fit other resin rear fuselage, making adjustments to fit. Use .080" drill bit or metal rod in horizontal stab holes for alignment. Clamp vertical stabilizer with flat scrap material. Super glue to KH fuselage and tack glue around vert stab. Remove drill bit/rod and continue gluing. Reinforce inside with styrene strips.
Super glue KH parts C62 and C55 (Arresting gear well) into rear resin fuselage.