Best way to handle high expense holdings in brokerage?

Best way to handle high expense holdings in brokerage? I have in my taxable brokerage about $25k in FFFHX, a 2050 target fund that charges 0.68% in expenses. I am thinking about transitioning to low cost index funds (likely all into VT). My question is basically- is it worth it to take the tax hit to sell FFFHX and buy VT, and if so, should I do it all at once or try to time it or spread it out? If I sell, it would all be long term capital gains, but I’m also subject to the NIIT as well as 5.5% state income tax. My unrealized gain on it is about 25%.