LN2 dry shipper suitable for snap-freezing?

Hey all! I need to do some transcriptomics on plant tissues. Previously I would always snap-freeze my samples in liquid phase LN2 and store in -80 prior to extraction. Now, I need to figure out a way to collect samples from the field. I don't think our safety regulations would allow me to bring liquid phase LN2, so I'm researching alternative options.

Does anyone try snap-freezing samples in vapor LN2 using a dry shipper? Is it a suitable alternative for liquid LN2, or is the process of freezing too slow? Would appreciate any insight, thanks a bunch!