As @Vikyek and @turbo2ltr said, it will be fine if you leave it where its .
If it is causing you issues or if you REALLY want to move it deeper, the sooner after the implantation the better as your body will be repairing itself.
If I was trying to achieve what you are asking, I would be, wriggling, pushing, manipulating the Spark2 further into the entry tunnel. This may be difficult depending on how much collagen/repair has built up.
once you get it to where you want it, Amal has suggested using toothpicks or similar to make a corral of sorts.
The prenatal vitamins are for collagen production, to help lock it down.
HERE is a link to a “toothpick” search, with other people in a similar situation.