That's not a Lally column. Lally is a trademarked name, and the one
in that article is a post jack (generic term), which is different than
a Lally column. You did point the guy in the right direction, though.
The OP can use a hydraulic bottle jack, a car scissor jack, a post
jack, a railroad jack or simply use a 4x4 at an angle and some
wedges. A porch roof doesn't have much weight, and each jacking point
would probably be bearing a few hundred pounds or so - probably
wouldn't be as high as a quarter ton.
I Googled this:
jacking up a porch roof to replace a column
and came up with this as the very first link:
Yup, saw that one before I posted. They use a bottle jack. I was hoping
to avoid buying 4-5 bottle jacks to do this. I have to lift the entire
roof (approx. 24') at the same time and leave it there
long enough to dig new footings, pour concrete, and install new posts.
This is also 150 miles from my home so chances are of me getting all of this
done in a weekend is slim so I want something that I can
put in place and not worry about it lowering the roof (ie. I worry about
that with bottle jacks).