Im an Engineering Surveyor mate and use a lot of software to do my job. I have found that sitting on a problem gets me introuble, so you are right!! Find an alternative for now and move on, then go back to it later. I have found that when I end up doing other things, UV mapping, modeeling a different section etc I 'find' my solution to the original problem The more you use it you will find by accident shortcuts etc. DONT give up on it though, keep it up and dont get mad or depressed like I do...LOL.

I dont use nurbs much so sorry I couldnt help more. You can use the curve tool on a live surface in poly, then modify to poly, then boolean dude. Thats how I get around it, there are a thousand ways to skin the cat mate.