Fiber laser for PCB prototyping

I have been looking for enclosed 20W fiber laser for PCB prototyping. I would first paint the PCB board with some spray paint and then I would use engraving laser to make my layout. I would remove metal with chemical etching. Process would look like this:

https://www.youtube.com/watch?v=pfTshCFJssI

I would like to have 175x175 engraving area. I expect that Raycus laser source would be sufficient. My challenge is to obtain target linewidth and gap of 100um. Looking for the machine specifications, my requirement should be doable. I have been in contact with few suppliers, but I have not received confirmation that I can do the job with their machine.

I have received sample engrave from one supplier, which is pretty close. The problem is that 100um line would be 30um and 100um gap will be 170um. It looks to me that there is some offset. I don't have experience of EZCAD2 software, but it looks like there is offset value for the hatch, which should solve the problem.

Does anyone has experience of making PCB with this method and would it be possible to get relatively cheap fiber laser to meet my 100um requirement?