To me, it depends on the subrate that you are using and the plant itself on how you plant it. Lets take moneywort for example. Thin plant with a strong stem. I split each bunch into two and cut the weight in half and wrap each bunch and plant.
The factor for me is usually keeping the plant in the ground. You can usually get one in there fine, but try planting a few right around it and one is bound to float away. At least this is how this happens for me. I am a bull in a china shop, btw.
Once the plants grow a few roots then you have what you need to plant them how you need to plant them.
I find that keeping them in small bunches untill they start to establish makes my work easier.