-- Load all page-attached texts
pagetexts = finale.FCPageTexts()
pagetexts:LoadAll()

for pagetext in each(pagetexts) do
    -- Create the text string
    local str = pagetext:CreateTextString()
    -- Check if the title text insert exists in the string
    if str:ContainsLuaString("^title()") then
        -- Create (and load) the connected FCTextBlock data
        local textblock = pagetext:CreateTextBlock()
        -- Set the line spacing to 90 % and save
        textblock.LineSpacingIsPercent = true
        textblock.LineSpacing = 90
        textblock:Save()
    end 
end