when doing battles with friends what would be better thunder wave to secure 100% paralysis
or would secret power which has a base 70 power and a 30% chance to paralyse (to deal damadge plus with decent chance of effect)
It depends. Who your opponent is.
Thunder Wave has a 100% paralysis, but does not affect Ground Types/Motor Drive.
Secret Power has 30%, and does affect Ground Types/Motor Drive.
I personally would go with T-Wave, 100% paralysis is better than 30%.
Well i would go with secret power because with thunder wave it has a 25% chance of not attacking which really isn't that good because it hardly works but with secret power you cause damage and if they get paralyzed that just makes it better for you in the long run. Now if you have a pokemon that will benfit from the paralyzing really well like one with hex then go with Thunder Wave