As you can see DIY is not as easy as it seems. The manufacturers have the advantage of testing different combinations and honing in on the best one. DIYers have the disadvantage of everyone having a different opinion and trying to find a formula that works without having start your own R&D department. So, unless you want to spend a lot of money and time trying different configurations, you won't be able to hone in on as good a design as most cable companies. That being said, DIY can save lots of money if you can find the right design online or from a friend that works.
Good Luck!
Good Luck!