Thucydides 1.85.2 need help on grammar

http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0199%3Abook%3D1%3Achapter%3D85

Archidamus, a Spartan leader, is concluding a speech. After recommending that the Spartans meet the Athenian threat by a combination of parley and preparing for war, then:

ταῦτα γὰρ καὶ κράτιστα βουλεύσεσθε καὶ τοῖς ἐναντίοις φοβερώτατα.

Trial translation:

You will resolve things most strongly, and for the adversaries most fearfully.

I take the meaning of βουλεύσεσθε to be “you will resolve things”. I’m guessing that there are assumed verb forms for “ταῦτα γὰρ καὶ κράτιστα . . . καὶ τοῖς ἐναντίοις φοβερώτατα.” But I can’t go any further.

At first sight, I would consider κράτιστα and φοβερώτατα adjectives referring to ταῦτα.

You will resolve on these things both very strong and very frightening for the adversaries.

I asked for help on this snip:

. ταῦτα γὰρ καὶ κράτιστα βουλεύσεσθε καὶ τοῖς ἐναντίοις φοβερώτατα

bedwere replied:

Oh, thank you bedwere; I can’t evaluate your reply, but to me it makes a lot more sense than my effort!

Yes, ταῦτα (which you missed in your translation Hugh) is an internal accusative with βουλεύσεσθε, and the adjectives (which I do not take as adverbial but as superlative adjectives) are predicative with ταῦτα.
Steven Lattimore well translates: ”These plans will give you the most strength and make you the most formidable to your enemies.” The language is heightened and dense, making a fitting conclusion to this very Thucydidean speech.

Many thanks mwh. I lost my way on this sentence. I must study the internal accusative.