Oxy-Fuel Piercing - How much to tilt from 90 degrees?

Does anyone have experience with a tilting head oxy-fuel CNC setup?

I'm designing a head for my Harris 98-6 machine torch (oxy-propane).
It is a high speed cutting torch (20 ipm through 1/4" steel) and I'd
like to design a tilt feature into the head mount so that slag
doesn't clog the 6290-VCC tip when I pierce. According to the
pictures that Harris publishes, the quality of the cut is incredible,
but you've got to keep the tip clean during piercing.

Most likely I will build in both rotation - up to 45 degrees from
vertical and torch height control (the THC is mostly for the plasma,
but if I cant the oxy-fuel torch over to 45 degrees from vertical I
would most likely have to lower the torch in the same macro).

Most of my cutting will be done in 1/4" to 1/2", but I have
aspirations to cut up to 4" on some projects.

So the questions:

1) Does anyone have experience with this kind of setup and any
recommendations / suggestions as a result?

2) How much should I tilt the torch from vertical so as to not to
contaminate the tip?

thanks in advance for any suggestions.

Bob in Florida