Transmission Fluid Change

[97CorollaCE]

My father has a neglected transmission on his 1997 Toyota Corolla CE (3 SPEED AUTO) w/ 80k on original fluid. It is dark and tinted a light brown color. I ordered my OEM Filter and Pan gasket. Please tell me if the following is correct..
1) Remove the pan and let the oil drain well.
2) Measure the oil that came out and scrape off the old gasket, clean the magnets.
3)Remove filter and replace.
4)Then put the pan back on w/ the new gasket.
5)Replace oil w/ fresh new Castrol Dexron III w/ the exact amount that drained out and take it out for a spin and run it through the gears. Check oil level and add as required.

Is that ok?

Now a few more questions..
I know not to over tighten the pan so it won't destroy the gasket but how tight is too tight? I don't have a torque wrench and is it required? Can I just tighten well and then in a few miles retighten?

Since the NEW ATF is gonna be loaded w/ detergents and loosen alot of crud I will do the flush again in a few thousand miles thats ok right? Lemme know your thoughts/ideas.
I can use Castrol Type DEXRON III right?

Can someone please e-mail me a copy of the page in the Chiltons manual on a tranny flush?

[dx-r]

Are you just going to do a drain and fill? If so than it's not going to drain out all the old ATF. I would suggest having it "flushed". It's when the lines coming off the trans is hooked up into a machine and the trans own pump flushes out almost all of the old ATF while the machine add new ATF in.