iwata HP CH modified to 0.20mm or iwata CM C plus 0.23



The HP CH is 0.30mm but I will modify it to 0.20mm which is better to make details HP CH 0.20mm or CM C plus 0.23mm ?
That all depends on the hand that is using it. I have seen pros use a .35 and get as good of detail as a micron. The Poor mans micron which is what you are talking about works great but lack the atomizing that you get from the Micron. Mainly what will fit your budget ?
I picked the micron over the poor mans but that was only due to recommendation from a couple of the pros I talked to and one of them being close enough to me for me to try both.
The HP CH is 0.30mm but I will modify it to 0.20mm which is better to make details HP CH 0.20mm or CM C plus 0.23mm ?

The Micron is a better brush, but that does not mean that everyone that picks it up will use it (or be able to use it) better than the HP-CH, with a .3, a .2 or whatever. An individual may find that for them, the Badger Sotar, or Badger Extreme Patriot is the brush that gives them the ability to produce the finest details. The Micron is still a better brush ;).

To be specific about answering your question - The Micron uses a different head system, and nozzle set up than the HP series. The way that the air is channeled through the Micron gives it the ability to produce a finer atomization than that of the HP series. In my opinion, the .23 Micron will produce a finer line than the .2 HP series brush. There is more to it than JUST that though - the Micron has a better trigger, tighter tolerances, etc... The deal with the Micron is that it requires the user to be a bit more diligent about paint reduction, air pressure regulation, and technique to take full advantage of. Not everyone gets along with them.

I have an awful lot of brushes, more than 60 now. Not one of them is the answer to every question ;). I have produced some of my most pleasing work with some of my most inexpensive brushes... A person does the best work they are going to do with the brush they feel most comfortable using.
The difference is minimal... Either are a good tool. Most can't tell the difference between 0.23 or 0.2. The ability to get detail has a lot more to do with the operator. Practice goes much further than the brush. You have asked most of your questions around what gets good detail, the answer is the artist.