I recently hiked with my wife from Crabtree TH to Deer Lake in a day. I assume you selected Gianelli to start higher up (8600 ft instead of 7160 ft) and avoid that extra 1500 ft of climb. We picked Crabtree (same distance to Deer Lake) to have more options for fishing and swimming. We went directly by Camp Lake, Piute Lake, Gem Lake and Jewelry Lake before getting to Deer Lake. We almost decided to camp at Gem Lake after a refreshing swim in there, but continued to Deer Lake and fished our trout for dinner there.
For us it was worth it to start from Crabtree. We didn't mind the extra climb and enjoyed our swims in Camp Lake and Gem Lake a lot during a hot day. Having several lakes as options to stop for the night and fish/swim there was our main driver for starting at Crabtree.
Have fun out there!