Provan and South denied deliberately deceiving the two Tauranga women or scamming them out of their money.
Lawyers Tony Rickard-Simms and Bill Nabney sought bail for their clients on medical grounds pending sentencing to enable them to get their affairs in order.
Judge Paul Mabey QC refused and told Provan and South they could expect to receive lengthy jail terms and remanded them in custody for sentencing on February 22.
Judge Mabey said he agreed entirely with the jury's verdicts.
"The view I take is you both committed this callous, cynical and deliberate fraud on these two ladies," he said.
"Provan, you lied to the FMA and to this court. South, you lied to the FMA."
Judge Mabey said Provan posed as an honest Christian man telling Gilmer she could "double her money" and Rowling she could earn more money than she could spend.
Eventually, after lots of requests, $40,000 was repaid to Rowling, the court heard.
Crown prosecutor Richard Jenson told the jury on Monday Provan and South were "a double act" who had systematically drained the bank account the women's funds were deposited into.
Judge Mabey agreed, saying both men were "equally culpable". He asked for a report exploring whether any of the $645,000 could be repaid.
Outside court, Rowling and Gilmer told the Bay of Plenty Times they were relieved and delighted by jury guilty verdicts.
"We feel justice has been served. We are so grateful to the FMA and the Crown prosecutors for all their hard work . . . and we both want to say a huge thanks for what they both did."
Financial Markets Authority's advice about scam investments:
Scams often involve being approached out of the blue.
Scammers usually talk about high returns at "no risk", only a few people know about and investors should keep it a secret.
Always double-check the investment is legitimate. Check the FMA's website to see if the business is licensed and whether past scam warnings were issued.