You are right. But if you solder leds together with pill, you can remove this set from hot plate and extra mass will also help to avoid fast temperature decrease.
All depends from pressure that holds pcb in place: Just how important is thermal paste? The results may surprise some people... Tested by Texas_Ace
If I got last question right, you want to compare two configs? P60 with foil is better, thread fitting is not best way to transfer heat. But (I have probably mentioned this more than 100 times) actual power is limited by host area.