Hi Ed.
Most folks just use the Dayton Audio poly caps from Parts Express. Last year I ran across a post by a fellow who used the Dayton caps to rebuild his M19 crossovers and posted the process. I can't find that thread right now, but there are
numerous M19 crossover threads from stock rebuilds to the Z19 upgrade. Here's where to find the Daytons:
https://www.parts-express.com/cat/cr...capacitors/292
Most folks use the Dayton NPE (non-polarized electrolytics) with
equal capacitance and
equal or greater voltage ratings as compared to stock capacitors. If Parts Express does not have the exact capacitors in stock, you can get the correct value by adding two or more capacitors in parallel.
https://www.dummies.com/programming/...el-and-series/
Unless they have broken wires or severe corrosion, there is no need to replace the inductors in your crossovers. Keep the stock ones.
Don't neglect to check the function of the L-pads. While listening to the speakers, move the knobs back and forth through their range. There should be no static, distortion, or dropouts. If they have problems, they can usually be cleaned and lubricated inside once the back covers are removed. If they are severely corroded inside, you may need to replace them.
If you already know all of this, please excuse my presumptuousness.
Just out of curiosity, why are you replacing the cones and the diaphragms? Are your drivers damaged?
Would love to see pictures of your Model Nineteens, including inside shots. Pics of your progress through the rebuild would be very helpful to other people who may follow in your footsteps. It never gets tiring seeing these timeless speakers.
GeeDeeEmm