Here’s a stop-gap version you guys can use—it’s simple and easy to learn:

TPL: total of party’s heroic levels (e.g. four 5th-level heroes have a TPL of 20)
TCL: total of the CLs of the encounter (e.g. a CL 6 and two CL 2s have a TCL of 10)

Estimating encounter difficulty:
Simple: TCL < 1/4 TPL, highest CL no more than best heroic level in party
Challenging: TCL at least 1/4 TPL but less than 1/2 TPL, highest CL no more than 1 greater than best heroic level in party
Extreme: TCL at least 1/2 TPL but less than TPL, highest CL no more than 2-3 greater than best heroic level in party
Overpowering (i.e. PCs should run or possibly face a TPK): TCL at least equal to TPL or highest CL 4+ greater than best heroic level in party

There—that’s a really simple method for estimating encounter strength so you can avoid killing your PCs. It’s not the same as the version in the rulebook, but it’s a greatly-simplified version of what I originally cooked up.