2 king size pillows should fit just fine on a queen size bed.
Although you might have to overlap the 2 king size pillows or they may hang off the edges of the queen size bed.
If the 2 king size pillows are a bit large and hang over the queen size bed sides then just overlap the pillows and they will fit just fine.
Also when you're sleeping you'll sometimes bunch the billows up so it shouldn't matter too much if the 2 king size pillows overhang some.
I've had larger pillows on a bed and just overlapped the pillows to make them fit and they worked out just fine.
I love large pillows as they are more comfortable and I like to basically hug the pillows with my arms and hands while asleep so a large pillow really makes it nice.