Alright, so I've enjoyed formal attire for some time now, but I've made the unfortunate mistake of purchasing a suite jacket and pant (38L) which wasn't the correct size for me, which I believe to be around 36L.

I've read that a suit pant should be about 6" less than the jacket, so I would assume a 36L jacket would requier a 30L pant, and the 30 is the waist size in inches? I'm not 100% certain so before I spent roughly $75 on the set, as they're sold in separate listings, I wanted to check first.

If it helps, this is the jacket and pant in question.
I appreciate any help on this matter..and while I'm at it, what are your opinions on the set?

Here's is a picture of myself sporting a tux for my sister's wedding. This is what finally inspired me to get a black suit and trust that a fitted suit will actually look good. Would the above suit I'm considering purchasing look good on me?

Again, thanks a lot and hats off to the fine men and women helping the fashion world out there, one guy at a time..