RE: 1/2A THRUST-O-METER
For the .074, buy MAS 7x3s. APC would be your 2nd choice. If you can find a soft nylon Tornado 7x3, it will never break and the performance is OK.
For the .061, buy Cox 5x3s and 6x3s from Xenalook...buy the rubber props. 2 of each should last you a lifetime. If you crash, just straighten the prop out.
The APC 5.7x3 might be the best for .061s, but they are fragile. Think of this prop after you refine your taste.
The soft flexible props I suggest are practical so that you will not need to constantly order new ones.
The local pylon racing record is held by a rubber 5x3 on a AME .061, not the hard plastic prop.
The thinking is that the blades flatten when the airplane turns [keeping the rpms up]. With a typical .049 engine, you will not have to worry about setting speed records with a 5x3, but as you gain experience flying, you will like the 5x3.