"I was hoping to have that finalised today but training today was of a high quality which then gives me some good decisions that I have to make moving forward to leave two of the boys out.
"I just want to have a look at the footage from training. I'd like to think I'm extremely thorough so I need to make sure that I am making the right choices
"Let's just say there's going to be some tough decisions being made."
Maguire has settled on his key playmakers, but faces a conundrum out wide with versatile pair Peta Hiku and Jordan Kahu and debutant Esan Marsters all in contention to play in the centres.
Hiku and Kahu are also capable of playing on the wing, but debutant Ken Maumalo is a specialist on the left flank, while uncapped Broncos rookie Jamayne Isaako is expected to play on the right.
"I've got a pretty handy spine there with Issac (Luke) at hooker, obviously Kodi Nikorima and Te Maire (in the halves) and then Dallin will be at fullback. That crew there will guide us around the park," he said.
"The centre position and one of the middle positions and possibly who can play back-row as well (are undecided)."
Maguire hinted veteran front-rowers Martin Taupau and Jared Waerea-Hargreaves are likely to start, but was still weighing up how to use towering youngster Nelson Asofa-Solomona.
Maguire has plenty of options around middle forwards and the back-row through the likes of Leeson Ah Mau, Herman Ese'ese and James Fisher-Harris, while Raymond Faitala-Mariner is more at home out on the edges.
"Those boys (Taupau and Waerea-Hargreaves) are definitely going to be in there.
"Again, that's one (Asofa-Solomona) there that we're going to talk about tonight as coaches."
The players have had little trouble adjusting to training at high altitude, with Denver sitting 1600 metres above sea level, but Maguire suggested the thin air could tempt both sides to take long-range shots at goal.
"A few of the boys had shots at goal from a distance and it seems to be travelling alright, so I think it does play a part.
"There was one or two (from beyond halfway) and they were quite a way over the posts too so they still travelled."
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