If our customer buys a tractor from a neighbor can we follow PMSI steps and get priority over both a prior blanket lien on the seller's equipment and a prior blanket lien on our customer's equipment?

Did you/have you recorded your UCC on or within 20 days of the borrower taking possession of the tractor. Will you direct payment to the seller and borrower in tanden to assure the train of loan funding.

From Article 9:
(g) Burden of proof in non-consumer-goods transaction. In a transaction other than a consumer-goods transaction, a secured party claiming a purchase-money security interest has the burden of establishing the extent to which the security interest is a purchase-money security interest.