The gear is quite pricey, might be able to hire it from somewhere though.
2k is more demanding. Cell will air dry in about 1-2 hours on a good day. 2k will need alot more than that which increases the chance of picking up dust before it dries.
This can be combatted using a curing accelerator, but this doesn't give as deep a shine as you can achieve with cell if you re-cut and respray.
Stick with the cellulose if you've already started, but keep your colour coats nice and thin.
Incedentally, 2k colour will stick to cellulose primer