rear main

Can anyone tell me how far the rear main needs to be presses in o a 351w 1 piece rear main? Please someone who has used the proper installer which I can not locate. I did not take a picture of it before I removed it because I purchase a 351w rear main tool OTC brand from scambay two years ago for this job and its not right. So I have watched about 12 videos on youtube and the first 6 used sealant on the outside of the seal must be installed dry. So I went on to 2 people say drive it till it stops,2 people say flush with the block,1 person says you need the right tool. One person said he made a tool and it is suppose to be 50 thousand deeper in the block than flush. I drove it in till it stops I usually make things flush but where the cut groove was way in there. My friends help a lot by telling me put it all together And I will find out. Worked at a Ford dealership for 20 years never worked on something this old. Thank You Joe