How much backing in meters do you need on your Yellow /Trout reel ? Was thinking 50 to 80 meters should do
The amount that you can get onto a fly reel is also what you should keep in mind. Also the type of fly line that you put on makes a difference.
For example, I have a 40+ expert line on my lamson reel. I can't even fit a full 50yrds(49m) onto the spool with that line. I also have a Snowbee cassette reel that can take about 65yrds (64m) with a 7wt rio gold line.
But with a standard WF line you should be able to fit 60m of backing.