Reagan was the best, but he whipsawed the dollar as much as any president, maybe more than any other. His "whipsawing" certainly put the economy on a gainful track though didn't it?
After all "Reaganomics" is STILL a divisive term used by the left.
Lest we forget the "tearing down of a wall" to boot.
Reagan tried to do what was practical. After Volcker raised rates incredibly high (which did help tremendously in restoring confidence in the dollar, but at the expense of a bad recession) and Reagan's policies kicked in, the dollar gained value very fast. That caused many companies to complain about being hurt by cheap imports. Reagan responded with the Plaza Accord which helped bring about the stock market crash of 1987.
In spite of those things Reagan's economic leadership was incredible, and brought about a recovery that didn't seem possible before he took office.