drilling
Check out mom's fish supply or gl*******s.com. I felt just like you, but I finally got the nerve up and made me a intake overflow\skimmer box, ordered a drill bit[$20 U.S.]and drilled 2 1-1/2" holes through the back of the tankand through the skimmer box, I then attached the bulkhead through the back of my 125 and through the box, using the washer and some extra gaskets I tightened the washer attaching the skimmer box with the nut. This works way better than an overflow box or any other filter for that matter.
I made a sump out of a 30 gallon long tote and an empty yellow tidy cats kitty litter box by drilling holes in it along the bottom. Although you can use any sump you want.
The best thing about this setup is if the power goes off there is absolutely no way your tank or sump can overflow as long as you drill a small hole in the input line that goes from your sump to your aquarium just below the water line.
If you have noticed I haven't mentioned drilling the tank. This is because it was the easiest part of the whole project! I purchased the bit from ebay but you can order the whole kit from gl*******s.com/mom's fish supply.com which includes the drill bit, skimmer box, gaskets,anti-siphon bulkheads and baffles. That is everything you would need and they are very cheap price wise and offer the greatest customer service I have ever experienced.
I hoped this helped! Will
P.S. Only thing you'll need to buy is plumbers putty
As long as you go slow with very light pressure
the glass is easy to drill. Check out utube
They have some great videos on this kink of
setup.