Muir will have arguably learned more about his charges from the first round of games, his side overcoming a determined Judea side 41-29 while Te Puke Sports ran rampant over Arataki with a 65-0 drubbing.
Rangiuru were 17-0 up inside quarter of an hour with tries to Jericho Yorke and Benet Kumeroa, both converted by Simon Rolleston who also added a penalty.
Judea pulled back a converted try before Lester Oliver extended Rangiuru's lead and Kumeroa added his second try, with Rolleston adding two more conversions.
Judea responded late in the half to make the score 29-14 at the break. Kumeroa made it a try hat-trick midway through the second half after Judea had scored two unconverted tries, with Hinckley Siaosi also crossing for Rangiuru.
It was one-way traffic at Arataki as Te Puke Sports' Jack Hollinshead scored 25 of his side's points with three tries and five conversions.
The other try scorers were Brad Armstrong, Kahu Craig-Ranga, Cheyenne Dalley, player of the day Grady Forbes, Ryan Wilkins, Luther Hirini, Josh Baxter and Matt Wallis.
The Western Bay of Plenty sub-union combined Development and Local Rugby competitions also kicked off on Saturday with eight development teams playing alongside Katikati, Eastern Districts and Pāpāmoa in two separate competitions.
Rangiuru development beat Judea 35-7 while Te Puke Sports development went down 27-14 to Katikati.
Eastern Districts defeated Pāpāmoa 22-0 in their Local Rugby clash.
On Friday, Rangiuru's women's side beat Waimana 58-0 at Centennial Park.
Draws for May 7
Baywide (2.45pm)
Mount Maunganui v Tauranga Sports, Blake Park; Rotoiti v Ngongotaha; Rangataua v Te Puna, Te Ariki Field: Arataki v Whakarewarewa, Arataki Park; Judea v Greerton Marist, Maharia Winiata Park; Rangiuru v Te Puke Sports, Centennial Park.
2022 WBOPRFS Development/Local Rugby (1pm unless stated)
Mount Maunganui v Tauranga Sports, Rangataua v Te Puna, Te Ariki Field; Judea v Greerton Marist, Maharia Winiata Park; Rangiuru v Te Puke Sports, Centennial Park; Katikati v Eastern Districts, Moore Park (2.45pm) Eastern Districts the bye.
May 8
Premier women
Waikite v Rangiuru 1pm.