Seems a lot of people have their own method of recovering finds, how do you do it?

Is it better to cut a plug/flap a little larger or smaller so as not to damage the grass roots per sq. in.?

LARGER plug is better. I've seen a few fella's try cutting 3" plugs for target retreival and all looks good at first 'til you go back a few days later to see the brown spots. The small plugs also tend to get sucked up by powerful lawn mowing equipment...not good. A wider deeper plug is always better. I usually cut a plug about 6" in diameter and just as deep...same length as the blade on my Jackson digging tool. Even better would be use Tom's shovel technique...just depends on where you're diggin'. Some people get a bit crazy when they see a fella wielding a space of any size in a park when they're metal detecting.

Good luck!