Usually 1:1 works well for rehydrating - but depending on humidity it can change. You can always add a bit more water if needed, so sure, start with less. If it ever has too much water? Dump in some Parmesan cheese. It will thicken it right up!

Now, for that teriyaki? I would come up with a sauce you like the taste of and carry it in a leakproof bottle. Easier than using dried components that are hard to get.

The beef? I would dry up cooked flank steak or similar. It would be good to have marinated it in a teriyaki sauce first. Looking at the ingredients they really haven't added that much stuff to the meal. Water chestnuts are easy to dry (dice up), use freeze dried peas and dried diced bell peppers. While labor intensive one way to do it is carry the veggies and meat separately from the rice and sauce. Prepare a bag of instant rice and set aside. Cover the veg/meat with boiling water and rehydrate for 10-15 minutes, drain off any water and add the sauce. Serve over rice. That is one way to do it, you could also make up teriyaki at home and dry it up. So lots of options <img src="/forums/images/graemlins/smile.gif" alt="" />