The two phrases quō..eō (hōc), tantō…quantō (hōc) can be broadly translated as ‘the more…the more.’ They are ablatives of degree of difference used to correlate to comparatives.
quō minus cpiditātis, eō plus auctōritātis, the less greed, the more authority
quantō erat gravior oppūgnātiō, tantō crēbriōrēs litterae mittēbantur, the severe the siege was, the more frequently letters were sent
The third variation is simply emphatic.
quantō plus crustulōs murī dabis, tantō hōc plus crustulīs eget: the mouse’s desire for cookies will increase in exact proportion to the number of cookies that you give him.
A&G note that this correlative construction later mutated to describe Cause instead of Degree of Difference.
eō mē minus paenitet, for that reason I regress less.
(Severe addicts should check out A&G’s note on this section 414an1, which details how the English ‘the…the’ is actually a direct descendent of these expressions, emerging from the instrumental case of a pronoun in Angle-Saxon, thȳ.)