Most people owe 15% of the LTCG. If you sold $5,100 of assets at a $100 gain, you would owe $15. So the actual tax impact may be much smaller than you expect.
It's also worth noting that tax loss harvesting only works as a short-term strategy. Stocks tend to double faster than you'd expect (at 7%, it takes ~10 years). Once they've doubled, how often will you see a -50% loss? -75%? It's very rare. Most equities make gains over time, so the longer the time frame, the less likely tax loss harvesting becomes.