i use 11x5-6, 10x7-8, 12.25x3.75 and 12x4, honestly the 11x6/10x8 are the best props for sport engines
some use 13x4 but its alittle big unless your engine is totally broken in (3-4 gallons through it)
13x6 is waaaayyyyy to big thats a prop for .75 engines.....unless your in japan and have big noise regulations...it kills the hp your engine puts out