I would remove and replant. The problem with being bunched so close together is they end up 'stunting' themselves effectively as there isn't enough space for roots and not enough nutrients to go around.
Think of plants in 'the wild', their mission is to get their seeds as far away from the mothering plant as possible either by animals eating them and passing them out elsewhere, the wind blowing them further a field or even firing them elsewhere! You get my drift..
If they have roots and your substrate is 'heavy' enough to plant them into, I'd 100% recommend this. You won't disrupt them, they'll love you more for it!
The lead weights also damage the stems etc