I have a suggestion for you.
At this point you can start if with v2 and upload with no hassle in the near future or,
Install the beta version alongside with the v2 (v2 will be your production site just to be clear) to see if other extensions are compatible with v3.
Just to be clear, start with v2 since updating will be hassle-free for K2 (you need to check this for other 3rd party extensions).
JoomlaWorks Support Team
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