If Knowles is a success in the NRL he'll be the oldest first time NRL player to achieve it. The successful players previously the Burgess brothers all in their very early 20's, Morley 23, Whitehead 25, Graham 26 & the oldest to be successful was Ellis at 27. Knowles will be 29 when Round 1 kicks off it's a huge task when all the others came early in their careers or just as their peaks were coming. The two most successful backs being Herbie & Widdop came across at very young ages.
Plath and Donoghoe since taking on the lock roles have won major club awards and last year Donoghoe at lock really unlocked Katoa.
Both Averillo and Donoghoe would be better no.6 options than the player they've signed for next year.