The 21-year-old has already thrown 18.41m in 2016, well over the 17.75m British Athletics qualifying standard.
But that was at an event without the correct permit to count towards Rio 2016 qualification.
In a final attempt for Rio, the Great Yarmouth athlete has created her own event at the University of East Anglia.
If she throws more than 17.75m at the competition it shall only count as one qualifying standard, even if she achieves the distance twice.
Two qualification standards are required for automatic selection, but the single standard would allow the performance director to consider her for a place in the Olympic squad.
She told BBC Radio Norfolk: "To go to the Olympic Games is the pinnacle of any athlete's career and I've got to achieve it through adversity, which would make it even more special after the mess around I've had this season."
McKinna's 18.41m throw at the event in Lincolnshire, put on by her former coach Geoff Capes, was 1.43m further than any of her other in-competition efforts this year.
However, it is still some way short of Judy Oakes' British record of 19.36m which has stood for almost 28 years.
McKinna has previously admitted to losing motivation following the split with twice Commonwealth Games shot put champion Capes, but said she now felt focused.
"I wanted to go there [to the Lincolnshire meeting] to prove a point that I'm over that and better than that now. That was really my sole motivation," she said.
"Because of the circumstances and atmosphere of it, I came out and produced that massive throw and I'm hoping that with a similar atmosphere I'll be able to do a similar thing.
"I don't think it's unachievable. If I thought it was unachievable I wouldn't have gone through all the stress of putting on the competition."
British shot putter Sophie McKinna has set up her own meeting on Saturday as she bids for an Olympic qualification distance before Monday's deadline.