Have u got the powder measure update kit? Works a little better that one that comes with deluxe kit. Your getting leading because, well, you are shooting lead. Why not use copper plated? Win 231 is a very dirty powder and it doesn't meter nice compared to titegroup. I was getting variations all the time with 231, not so much with titegroup.
I don't have the patience for the Lee scale so I got an electronic one. First round, decap, prime, remove case and weigh. Tare electronic scale, insert case into press, charge with power, remove and weigh the charge. I used to do that every 10 rounds, now only once when I start reloading for the night. If you are below max loads, +/- .3 grains is no big deal.
If you can find titegroup, buy as much as you can, it's cheap and it burns clean. 4.2 grains behind 124 gr Berry triple plated round nose shoots really nice. Last time I bought titegroup cheap was $24 for a pound before the shortage... Now it's hard to find.