size of transplant flats?

I saved a lot of my flats from last year, and I want to use them for a bunch of seedlings this year.
My question is: most of the 6-pack containers are quite large - about 2'' deep and 1 1/2'' or 2'' squares (width at top). Are these too big to transplant very small seedlings into (ie, once my seedlings come up in the little containers I use, can I put them directly into these larger containers? or do I need to have them in smaller containers and then transplant into these when they get bigger?) I'm worried about damping off and I'd like to get all my materials ready so that when I start growing, I'll be all set.
Any suggestions? I'm growing tomatoes, peppers, eggplants, and several types of annuals if this helps...
Thanks,
Mara

The ones you are mentioned are all fast growers. There is no reason that you can not plant directly in the 6-packs. You can also germinate the seeds in plug trays (smaller plugs) and then transplant plugs into the 6-packs later. Both methods are fully acceptable.

The size of the six packs you mention are usually for a second or third transplant or for layering and shrub cuttings that take a long time to get to planting size. They will give you 36 plants per flat. The more usual 6 packs are 72 to a flat and are more economical for annualsand other plants that will transplant directly into the garden or for the first stage of perennials.It is a bit more difficult to maintain heat and moisture but the space savings are worth it to growers. Jessamine

Jessamine,
Do you think it would be bad for my plants if I use them? They'd have more room to grow, but could I use them for first transplants? Obviously, I should get some smaller ones because space is an issue, but right now economics is more of an issue for me, and the plants are just for me, so I thought I'd re-use the ones I have...
Thanks,
Mara

Hey Mara, as long as you wash them in a 1 to 10 bleach/ water solution they will do fine. The problem I see is they use twice the amount of soil per plant than the standard 6 pacs. If you need only one or two flats, go for it. For more than that you would be better off paying the $.98 each for the 72 division inserts. They are available at most Ace Hardware stores. If you can find the clear tops by themselves they are a work and seedling saver. Use them over and over again.The combination packs sold by places like Wally World are a bit flimsy but can be fairly economical to get started. Most of the time your seedlings won't need to be moved to a bigger container before you transplant them into the ground. Jessamine