I've always had good luck with small sinks/small chips all the way up to 486 CPUs by this method:
Take heatsink, smear heatsink compound over surface evenly. Leave a small area of each corner bare.
Do the same with the chip you intend to put the sink on.
Take a pin (so you don't end up shooting superglue all over) drip superglue on it and use this to apply glue the the bare corners of the chip.
Put the heatsink in place, don't slide it around, just straight on and hold pressure till glue sets. With superglue, a few seconds usually.
Need very little glue, 1/4 of a drop per chip should be plenty.
Voila, heatsink stuck in place, heatsink compound without epoxy mixed in unknown ratio over the core, just the corners with less than ideal transfer. Which with many chip packages isn't an active portion anyway...think CPU, outer 1/2" of the ceramic wasn't over the 'chip' itself back in the pre flip chip days. With ram chips, not nearly so much extra package, but not nearly so much heat and the edges are the coolest to start with.
Good luck
--Mc