How tight is TAG play considered?
Is playing 78s in late position still considered TAG? or is it too LAG?
what hand range do TAG players normally play?
Ranges would be along the lines of top 5-10
hands in early positions, top 20 in late positions, and calling a raise will most likely be a sign of a solid hand. That would be with few reads. With reads (time spent with a group), those could expand 20% or so.
TAG players are generally not adventurous. They will however understand that in late position, if they can
open the action, they can easily play ATC
IF their table image is TAG. A very good TAG will know what their table image is and generally won't abuse this. A LAG player who also understands this situation, will tend to abuse it, partly because they either don't care what you think, or they are carefully crafting an image.
A good poker player will know when to use either TAG or LAG, as situations call for. Since it takes a few orbits to get classified either way, one should have many hands against a player before making decisions on how to play against a particular player. After you have sat with a player for an hour or so, you should have some idea about how he is playing that day. Caution that he will also have some idea about how you are playing as well.