cast iron rough in

hello,
I have a rough-in in my basement....there is a 4" cast iron pipe sticking out about 4 inches high...no flange....there is also a 2" pipe roughly a foot away from the other one; the soil stack is about 2 feet away from both pipes. I was hoping to use the 2" pipe as a sink drain as well as the vent for the toilet....just curious if that is OK.....

now my real question....I need to install a flange on the 4" pipe, but first I need to cut the pipe down about 2 inches.....what is the best way to go about this...

I don't know what type of flange to use or how to cut the pipe down?

any suggestions would be great.....

i called a plumber here in MN and he said its between 3-4 hours....or 3-500 dollars......I was hoping to not have to go that route.....

flange

The way I would do it, as long as there is an opening around the pipe for the flange to fit, would be to attach the flange to the pipe with a lead/oakum joint. Then break the cast iron pipe off flush with the lead using a hammer and finally calk the lead tight just like any other joint.

from what I understand...the lead/oakum joints aren't really a DIY thing....
I thought they were mainly for the experienced plumber???

is the flange that goes inside the pipe a bad idea???
or should I use a compression flange (I think I have seen one)???

and would a hacksaw blade cut through the pipe??
I wouldn't want to hammer it cause that might lead to other problems (cracks)???