Experience with underventing and with the pompador style using a medium light density - combined or individually? pros and cons. Personal experience prefered. Thanks.

When bases were more substantial, thicker & more visible, underventing was a good way to disguise the front edge of a system base.
Nowadays, its not really necessary because the edge can disappear on its own.
The problem with undervented hairs when they were around was that the base of the hairs got affected by the glue attachments and invariably didn't last long or clumped together after time.

However, short fine baby hairs at the very front of a system (but not undervented) are still a good way to disguise an imperfect attachment.
When I get a new system, I take the very front row of hairs and run a razor comb over them and this creates fine shorter hairs that fall randomly and break up the hairline.

That funny because I thought about that (razor comb) but didn´t know if it was possible. Thanks