Most citrus trees from seed grow as clones of the mother tree or very close to identical. The seedlings are susceptible to wet soil diseases when they are small and often die if special care isn't taken to get them through their early growth. I will plant a lot of seeds in a small area so that as they sprout and grow the collective group of trees will use the soil's water up quickly so that the soil moisture doesn't have time for pathogens to attack the trees roots and trunk base.
I am curious as to what your plans are for these seeds, do you plan to graft them or plant them directly?
I have some from seed Meyer and Eureka lemons sprouting similarly in some pots in my windowsill, and some trifoliate orange seeds sprouting outdoors. I am in 7a and the gist of my plan is to graft lemons onto the trifoliate rootstock and see if I can get them to survive outside with the help of a micro climate and/or winter cover.
Your poncirus trifoliata rootstock should add about 5F cold hardiness to each variety of lemons you have. that should take your Eureka lemon down to the low 20s-F and your Meyer lemon down to the high teens-F. You will need to be prepared to provide 25F heat rise to keep your trees alive for a once in 10-20 year cold snap. Lemons grow fast so you'll do better if you can grow them on their own roots to a bud node count of 75 or greater, 5-7 feet tall, before grafting. On PT the grafted bud will grow with closer bud nodes and should reach fruit producing maturity around 2-3 feet tall. a 5 foot tall tree is a lot easier to protect than a 9-10 foot tall tree. The Meyer lemon will not grow true to seed and will taste different but possibly quit good.
I am using mine to plant a hedge row on my property.