Walter, the 1617, MR23 and 1619 all use the same quick change adapter and the same PC style adapter. Bosch's steel bushings are better for rough construction but for home woodworking the PC style in brass is the best option. This is for a couple of reasons: Brass ring nuts will not come loose the way steel ring nuts do which will ruin your cut and possibly your bit. Brass is soft and will not chip the carbide tips should they bump against each other when swapping bits. The Bosch quick release adapter lets you swap or remove/install bushings without changing the bit height. This is a big time saver and no tools required. The sub base plates on current models can be adjusted for perfect center which is critical to getting good results with guide bushings. Bosch offers a centering cone which properly aligns the sub base plate. As long as the sub base plate is not removed this should last indefinitely.
PC style guide bushings come in two types: a set with different collar lengths and a set with all the collar heights the same.(a hair under 1/4") The second option is the one I recommend. This allows you to use 1/4" material for all your templates.(Saves money on template cost, is lighter and easier to store) Woodcraft sells a set like this.
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