Power brake conversion proportionate valve question

[Leinhit]

1960 Apache C10

I haven't been able to find this answer anywhere. I'm interested in getting the power brake conversion with booster installed in my truck.

However all of them that I see say they are for disc brakes out front and drums in the back, I still have all four drum brakes and will for a year or so until the next upgrade

Is there a harm in installing this conversion with the disc / drum proportionate valve? What do I need to do to make it work with my drum / drum setup? Knowing in the future I will get disc brakes on the front at some point?

*Has a side question I was interested in a hydro boost brake system however I do not have power steering so I don't understand where it would get the power steering pressure from? A standalone electric pump that runs like an electric fuel pump maybe?

Any direct links on what to purchase would be appreciated.

Thank you