As VB stated, there is weak and strong Salvia leaf, it all comes down to the % of salvinoran A that is produced by the individual plant. Even if it's weak sally D leaf, you can get a friend to pack cones for you and just do a few in a row for a decent trip.
I personally can't stand this substance. Every time I have used it from straight leaf through to 40x it has just been extremely irritating and I have wanted it to end as soon as I peaked. I find it's effects are very rough in comparison to say DMT and it gives me very unpleasant body sensations.