It is the final hit-out for his new squad before they open their Championship campaign against Taranaki at Tauranga Domain on Saturday, August 20, at 2.35pm.
McMillan says he and assistant coaches Rodney Gibbs and David Hill learned plenty from last week's game against Northland in Whakatane.
"There was lots that we liked about our performance against Northland and we are going to be better for the hit-out against Auckland.
"But we got exposed in a few areas and that was really important. It would have been nice for it all to have been perfect but we knew it never would be.
"We wanted to know what other teams were going to do and how referees were going to referee the new law variations."
Seven players on debut for Bay of Plenty against Northland all demonstrated why they were selected in the squad, McMillan said.
"There are a few who are not household names even within Bay of Plenty but they all put their hand up.
"I thought (halfback) Luke Campbell was very quick in his distribution, speed to the ruck and his decision making was pretty sound. That is going to be critical for all teams moving forward that the nine has a big engine and a lot of accuracy."
McMillan also commented on the Baywide Premier 1 final played on Saturday won by Rangataua Sports over Mount Maunganui Sports.
"I thought it was a fantastic occasion and have mentioned to a number of people that it is probably one of the best club rugby games I have seen in about 10 years.
"It had passion, it had skill, it had emotion and it went right down to the wire.
"You could not have asked for a better advertisement for Bay of Plenty club rugby."
The final was played without any of the contracted Steamers players which showcased the improved depth of talent in the Bay.
"There will be people saying the Steamers should not be playing in any final moving forward and others who want our players playing," McMillan said.
"I've always maintained I want our players playing so ideally in a perfect world we start our club competition a week or two earlier and everyone will be playing in the finals."