Light aircraft pilot reported an NMAC with another light aircraft in the pattern at PLU airport.

Narrative

The pattern became quite busy with 3-4 training aircraft and 1-2 others all of them faster than my aircraft; so I announced on CTAF that I would depart pattern from Crosswind leg. Did so and flew VFR at 1;500 ft MSL in circle of 10-20 miles diameter centered on this airport. Upon return; announced my location over well-known local landmark approximately 5 miles from airport 1500-feet MSL and 'maneuvering for the 45-degree entry to downwind for runway 35. About 1 minute later; I observed a faster; low-wing SEL speed past slightly below and off to my right between me and airport pattern. On CTAF I heard a call as 'Aircraft Y ... west of airport heading north to enter the 45 for downwind runway 35.' There was no more detailed reference to color and I was not familiar with a model known as 'Aircraft Y' later determined to be this a/c; so I was not entirely clear of the situation; but I did change my 45-entry maneuver to follow the other a/c to the downwind leg.About this time; an in-bound a/c had announced 'on a 10-mile final RNAV approach for runway 35 traffic permitting' as too-often is the case for flight-training operations at this airport. Proceeding downwind; I observed that I appeared to third in pattern behind an older high-wing #1 that was slow and using a long final approach; then the Aircraft Y low-wing as #2 that extended to turn a late Base leg to allow #1 on Final.Extending my own downwind leg; I turned Base and wondered about the in-bound RNAV approach that may have announced '5-mile final straight-in' but I did not have it in sight. While looking for this a/c; I lost view of the low-wing 'Aircraft Y' that announced it was turning Final; but believed that its higher speed would still have it ahead of me at a safe distance.The near-miss happened when I announced 'Turning Final' and immediately saw the low-wing a/c in my path crossing right-to-left on his Final. I immediately stopped my left turn and dove abruptly to clear underneath this aircraft and announced my actions on CTAF. Departed to East of the airport and climbed to 2;000 MSL while circling around the north-end of departure; outside of Crosswind pattern; and continued away to turn back and announced 'my intention to make another 45-entry to downwind for runway 35.'Upon completing that successful landing; I met the pilot of 'Aircraft Y' and he commented that I must not have seen him on final; as he had obviously been aware of the near-miss. When I acknowledged that I did not until the last minute; he stated that his 'Final had been longer than normal due to the slow high-wing #1 that he was following' making a long final; too.Obviously; I need to keep more aware of numerous (faster) aircraft that are sharing the traffic pattern. And if I cannot totally confirm sighting of another aircraft of unknown type; I should inquire on CTAF for clarity. I am not sure what I can do about aircraft that announce they are inbound for a straight-in RNAV practice approach when there are already multiple a/c in the pattern.