Deer Hunter,
What I like about this site is the honesty and willingness to help. Example: [eerw] "you should see all the parts in my junk pile". Ha, bet my stack of 1911 parts ALONE is higher than his CZ stack.
Anywho, here's a suggestion on getting that new sear right on the money, first time, everytime.
Objective - to have as close to -0- clearance as possible between the sear arm contact area and the manual safety "pad" when the safety is up. However, you will notice virtually no difference if there is .002 - .004" clearance in this area; the saftey will still work reliably.
I have an old needle file that I have sharpened to a very fine point. This is my "scribe" tool for fitting the sear arm. With the new sear installed, the safety in the down position (off), take the scribe tool and engrave or scratch where the sear leg and the manual saftey pad intersect.
Remove the sear block and using a Dremel (yes, I said Dremel) "green" grinding wheel (I'll take a pic and post of the one I use), gently grind the sear leg ALMOST to the scribe line. DON'T grind into the scribe line. The scribe line also allows you to make sure the cut is "square".
Chances are, the sear will fit properly the first time, if not, grind just a fraction more and re-fit.
I have done this 6 times, each time was near perfect the first time.
Hope this makes sense.