The 32s allowed me to vernalize more nuts fitting more in the same space in the fridge. However, I didn't really like the extra transplant into 18s. If you have few enough nuts that you can fit them in 18s in the fridge, I would go that route. I also really like the 18 express trays over the regular 18s. They will last much longer and you can rearrange cells in the tray. This allows me to arrange my trees by height. I use fluorescent lights because they are cool and can be placed close to the tree. I hang my lights so I can adjust the height. I hang them at an angle so tall trees on one end are the same distance from the light source as the smaller trees on the other end.
This year, I only have about a tray's worth of nuts, so I'll probably go straight to 18s. Just thought I'd pass this on if you haven't ordered yet.
Thanks,
Jack