Number of fish should never come into it. Tipping should be based on the whole experience with your guide. Ghillie's should never rely on tipping or judge on the amount given to them. Just give the amount that you truly think reflects on the day you have had.
Albury suffer bad fish lice problems. they try and get rid of the problem by draining and liming the lakes, but the problem lies in the marginal plants. I'd take the fish to tony, and get a free ticket.