Does τοιούτοs always refer to what precedes ? Smyth is not very clear on the point. It seems that in Plato it often refers to what follows.
I don’t have a grammar to hand, but my instinct is that it’s a case of almost always. Even when enjoined by τις as in τοιοῦτος τις.
I can’t summon up an example from my memory contrariwise (obviously, not a huge point, but still) and it makes sense given the etymology τοῖος + οὗτος.
Sorry I didn’t understand you saying it may refer both backwards and forwards, right?
There is indeed a before and after distinction that can be made with τοιοῦτος and τοιόσδε, as you can read here:
Besides that contextualisation wuthin the flow of the narrative, there is a lot more to τοιοῦτος than simply before and after, however. The demonstrative τοιοῦτος marks a word or phrase to show its relationship to other words or phrases. Those other words or phrases (either before or after) are marked with other words.
Are there words like οἷος, ὡς, ὅς, ὅσπερ, οἷόσπερ, etc. in the contexts you are reading?