here is a picture of what to sharpen I have marked it in black. as far as tips im not exactly sure what effect round vs pointed would have except the way the water came off the prop someone with more knoledge would need to step in on this one most of the props Ive done have been prather or x and y series octura
you asked how you know if the prop needs changed the way I tell is listining to how the engine sounds mainly also how the boat is reacting..If the engine sounds like its working to hard -smaller i go, if its not working hard enough I go bigger thats the easiest way for me to explane it.. Im no expert in props but I can pass on what I have learned from actually doing the work and listining to the people that know more than I do when they try to teach me something new... I hope this answered your questions ok