General Size Recommendations:
.025 - Heavy Trout Flies or Light Salmon Flies (#2-#8),
.030 Good All-Around Size for Salmon Flies (1/0-#6),
.035 - Very Heavy Salmon Flies of any size.
We generally recommend using EITHER spooled lead wire or barbell eyes but not both. Using both seems to "deaden" the action of the fly. Wrap the lead wire from a point on the hook shank directly above the hook point to 1/8" behind the hook eye. Wrap in a bump of thread in front and behind the lead to keep it from sliding on the hook. For added strength you can cover the lead with thread wraps and/or place a drop of glue on the lead.