I am doing my first ever 1911 build. Based on a 80% lower and a mix of wilson, ed brown, les baer, and swenson parts.

The only issue i have run into so far is the thumb safety not going flush to the frame. Im not sure exactly where it is hitting but it appears to be on the sear.

How should i go about fixing this issue? I'll try to put up some pictures tomorrow.

If the safety is hitting my the legs of the sear that just means you need to CAREFULLY remove a little more of the safety. Use some marker on the safety and reinstall to see how much to take off ( the sear will remove traces of the marker dye). When you do this dont wiggle the safety around, just press firmly. File off less than you think and refit. Ideally you don't want the sear to move AT ALL when the safety is applied. There are lots of tutorials on exactly how to do this, best if you read those closely. A misfit safety is very bad ju-ju.

Depending on the relative cost of the parts, it's also acceptable to remove metal from the sear.  When a sear is $25 and a good ambi safety is over $50, I've cut more off the sear.  If and when the sear needs replacement, you won't need to worry about having yo fit a new safety.  

Of course the sear is harder to work on with a file, due to its shape.  The thumb safety lug is easier to file to fit.