We have had this conversation in Chia Plotting: Is there any advantage in plotting k33, k34, k35?
The thread got pretty long so I will summarize.
Basically, a K33 is twice as valuable as a K32, may have more long term viability and, contrary to popular belief, plotting three parallel K33s takes less time and is easier on the computer than 6 parallel K32s.
K33s are slightly more than two times larger than two K32s. I can fit 32 K33s on an 8TB drive with room left for a K32. I could fit 66 K32s by themselves, so I am only losing one K32 per 8TB HDD. Of course with different drive sizes you have to make this calculation individually.
If I could, I would plot K35s. There is a possibility that we may jump straight to K35 when K32s become useless. 4 K35s fit nicely on a 10TB HDD. I would be plotting K34s now if they did not fit so badly onto my 8TB drives. Even trying to plot 2 parallel K34s would choke my machine anywaze, lolz!