The spread method should work fine. Personally I'd go for the dot method but you'll see an improvement regardless.
The idea of thermal paste is to fill in microscopic gaps between the CPU/GPU so you don't have little pockets of air acting as an insulator.
So put on the recommended amount (half a grain of rice?) spread it out a bit, not to the edges though. Then when you put the heat sink on apply as much pressure as you dare. Screw down the heatsink. Reassemble everything and you should be golden