How best to proceed..? (J1.5.26 -> J3.3.1)

[NathanPOL]

Current Live Site is on Virtuemart 1.5.26, we've purchased and tested SPUpgrade.
We have 800 Products 120 Registered Users on VM 1.1.3.
All our plugins, modules, extensions work on Joomla 3.x which we plan to migrate to.

As we've tested the site migration tool SPUpgrade with positive results, we plan to migrate the live site from J!1.5.26 straight to J!3.3.1, but where does that leave Virtuemart?
Is it absolutely vital that we wait for a stable release of VM3? If one of the test versions (ie. 2.9.6) works for us, could we move over all existing VM information using CSVI Pro?

We just want all the right information on the new 3.3.1 site, we'll worry about putting it all in the right place later!

So my question is as follows; how would you proceed?

(P.S sorry if this is in the wrong place)