Some people place two seeds in every cell and cut off the smaller plant. I don't do this. Some seeds I know will give very good germination and I might sow them one to a container like a cellpack. Don't be afraid of a few empty cells, nothing is lost. Others I usually sow many in a tray or 3" pot, trying to space them out evenly. I then either transplant straight to the garden or move once to larger containers before they go in the garden. Transplant early and carefully and you shouldn't have problems. Hold transplants by the leaves, not by the stem or roots. I find that larger Lavender don't transplant well, but it can be done as with all plants.

P.S. I don't like the peat pellets.

shrubs and bulbs has given some good advice already

I guess all I can add is that some seedlings will be happy to stay in cells for longer than others. If your seedlings are getting too large or just not progressing, it usually means theyre ready for something bigger. tomatoes I usually pot up quickly into small pots, just a few days after germination, and grow them on until theyre ready to go in the garden. generally I dont like putting tiny seedlings in the garden because theyre more vulnerable to things like snails and slugs just chomping them off and I dont use snail pellets so I prefer to pot them on until theyre a little bigger.

I don't like peat pots either but you already bought them. Because you don't want many plants and are using the peat pots I would do 3 seeds per pot because you have more seeds than you will use anyway and with your scissers cut off the extra plants. I too would plant up to 4 inch size before planting in the garden. My method uses four inch pots for seeding 9 seeds per pot evenly spaced. I water by standing the pot in 2 inches of water until the water wicks to the surface of the soil. Next I let pot drain and cover with clear plastic wrap and a rubber band to keep plastic tight. As soon as germination is apparent the plastic is removed and the light and air circulation is increased. When the second set of leaves appears I transplant most seedlings, one to a four inch pot. When roots are visible at the bottom of the pot they are ready to plant in the garden. Al

Thanks for the advice. From what I gather from your comments, peat pots are not the best thing for starting seeds and transplanting. Will start seed in what I have and transplant to 4" pots for grow out before going in the garden.

One thing to beware of with peat pots - if you plant them in the ground, be sure to cut the sides down to below ground level or to plant the pots deep enough that the sides are underground. If they stick out above ground they wick water away from the roots and stress the little plants.