I currently have 6 seedlings in pots.
Seedlings? Are you trying to grow citrus from seed? If so, you will be disappointed with the results. Yes, you can get the seeds to sprout, and yes, they will grow into citrus trees. However, they will not be true to the parent plant, and so you never know what you will get in terms of fruit size, flavor and juice.
The only way to get reliable fruits is to graft a cutting, known as budwood, onto rootstock. As the budwood joins to the rootstock it will develop into the scion, or top, fruit-bearing portion of the tree. This will be genetically identical to the parent plant from which the budwood cutting was taken.
I seem to remember reading that the Meyer lemon is about 100 years old, and all Meyer lemon trees are genetically identical to their original ancestor.