"Starting Prop" normally means the same thing as "break in" prop.

Remember that certain engine lines produce more power than others.... so there may be differences in the suggested prop tables.

Your .40LA engine is rated for an 11x5 or 11x6 prop according to OS's site.

However I find that it runs better with a 10" prop as it is not a "strong" .40 engine since it is of the "budget" variety.

I also run a .46LA with a 10x7 prop which equates to an 11x6 in terms of load on the engine, that is recommended for standard .46 sized engines.

Go by the 11x5 recommendation from O.S. and adjust accordingly. This means you can go one size up in pitch if you go one size down in diameter and get the same loading on the engine... ( and yes I'm being very loose about this to the cognizanti ).... or vice versa...

So 10x6, 11x5, 12x4 would all work.

On a lighter plane you could also use 10x7, 11x6 and 12x5's.