If you want a cheep solution for a bowpress you should take a portable bowpress. They are not as comfortable as normal presses and also not this secure but are prtable and less in price. A good portable bowpress is the one from nitehawkarchery (or so).
You should take the lengths that are displayed by the chart as long as you can identify your bow exactly with the bows that are listed there. What says the sticker that should be on your lower limb?
You may go to the shop and ask why they sell this bow with the wrong strings/cables or should have a closer look to the limbs and so on.
(2) Martin ShadowCat 2010