ok my aim is to tone up/maintain and hopefully increase a bit of muscle mass.

I've been reading that doing high reps (12-15) and light weights, still to failure though, isn't a good idea and it doesn't really give good results..

So then my options are either doing sets of 10 reps or set of 8 reps... or doing a pyramid type set.. 10-8-6

what do y'all recommend ?