Jerry, question on your statement:
The heat transfer is hindered anytime there is a discontinuity in the metal between the surface of the bore and the water jacket or cooling fins.  Even though the junction between a sleeve and the cylinder is a tight press-fit the heat flow through this junction is dramatically hindered.

Would the aluminum (NICKELSIL PLATED) sleeve conduct heat better than a steel sleeve, what benefits would a LT500 piston get from this setup?