Some suggestions- 1)Use the .025 to tie some stonefly nymphs- big ones. Smokies fly fishers have concentrated on the Mayflies and Caddis and neglected the huge Stoneflies we have. Look at the size of the nymphal husks on the rocks stonefly nymphs are large. If you follow the fishing reports, the guys hunting those big browns aren't throwing #14 and 16's.
2) Lead free wire is lighter than lead. So we have more bulk for the same weight.
3) A rule of thumb is to use lead wire the same thickeness as your hook shank.
4) A problem most freestone nymphers have is getting their nymphs deep enough. I tie my stonefly nymphs with two tungsten beads one at the thorax and a brown or black for the head. I wrap lead free wire between them. I dubb over the bead and wire at the thorax.
5) With the problems at the tail, wrap a little dubbing.
6) Is where we put the wire on the nymph (other than altering the nymph's shape) really a factor after we attach a tippet resulting in drag, other forces? My personal opinion -90% of time its more important to get the depth.