Hi firewns,
I think the merit that is gained by circumambulation of a stupa is because of one’s respect (sadda) towards the Buddha. I think it is one’s thoughts during that time that will lead to merit. So one can circumambulate a stupa clockwise and gain demerit if one is thinking bad thoughts during that process. In the same way one may gain merit even by going anti-clockwise if his thoughts are pure etc. Saying this there are energies etc. that may play a part in all this, which I am not too familiar with.
Silabbatha paramasa refers to a view that one can attain nibbana through performing rights and rituals. It doesn’t mean that someone who doesn’t have silabbatha paramasa will not perform rights and rituals. It is just that he knows that performing such rights will not lead to nibbana. He can do this out of respect / shradda etc. And this shradda can help him gain panna which is vital to attain nibbana.
In the thera gatha different monks explain how they initially got on this path, many many lives before. And for all of them the start has been shradda towards a previous Buddha. So such “rituals” (done with proper understanding) can be very helpful on the path.