When it changed last year in December, I quickly made a direct DIK
to the church for 2018 the last week of the year (I had already done one for 2017).
In August 2018, with the market so high, I took profits and DIK'd for 2019 and 2020 via a DAF. I will be making my first 2019 tithing & FO payment via the DAF soon. So far, I really like the DIK because it is hard to estimate one year in advance, and even harder two years in advance. Not only that, I can donate to other charities through the DAF and not lose the writeoff, although after tithing, I am pretty stingy.
Unless the tax law changes, I plan on bunching my donations. The last year I work, I may make a 4 or 5 year donation via a DAF.