If you have already done Fuhrer Finger, Furher Thumb is a decent alternative to add to your tick list. Use the standard approach and high camp for Kautz Glacier and Fuhrer Finger. High camp is located on the west side of Wilson Glacier below the Turtle Snowfield. Starting at 9,200 feet rock outcroppings up to 9,400 feet provide a number of suitable camp sites.
From high camp traverse north-northeast across the Wilson Glacier toward Fuhrer Finger. Crevasse navigation will be necessary. Fuhrer Thumb will be the snow couloir immediately west of Fuhrer Finger. Beware that crevasses cut across the entrance to the Fuhrer Thumb couloir.
Climb directly up the couloir (up to 45 degrees) At roughly 10,500 feet you will reach an ice/ rock band that will offer to go left or right. Your decision will be based on snow/ice conditions. I decided on left.
Continue up the couloir until you connect with the Fuhrer Finger at 11,500 feet. A right traverse may be necessary earlier depending on route finding and conditions.
Alpine start recommended (1:00 or 2:00 AM). Rockfall began to occur at twilight.
Overall climb was fun with hard snow and ice.