What program/process to use for weight painting this HDT Hair?

[shade549]

I'm trying to convert hair to HDT SMP following this tutorial using 3DS Max 2015

https://www.youtube.com/watch?v=sdb2VV7oXkw&lc=UgwDIAOD1p9OkFJhKZl4AaABAg.9Wev5anrBfQ9XqH-rv4LgT

 

But the mdodel used in the tutorial was simple and it was easy to use 3ds Max tools to weight paint it.

 

The hair I'm using has a lot of overlapping vertices and complex shapes, where the method by selecting individual vertices to weight paint is too difficult and time-consuming.

 

My hair looks like this:  https://imgur.com/a/sK22ZTG

 

 

Does anyone know a better way to weight paint something like this hair?