I think the easiest thing would be to get a piece of paper - draw a line on it 1/4 inch from the edge - set it under the presser foot and see how far from the edge of the paper the edge of your presser foot is when the needle touches the line you drew.
One can learn to 'eyeball' where the edge of the fabric is after you have figured out 'exactly' where it needs to be in relation to the presser foot you are using.
It may barely stick out - it may stick out 1/8 of an inch - it might be 'inside' the presser foot by 1/16 of an inch. After you figure out 'where' that 1/4 inch is, that is half the battle.