Heading towards Bocognano, go through the tunnel and park at the Sellola Bridge, where there is a small car park on the right
(S/E) Follow the track leading to the dam and carry on to the gate. Do make sure you close it behind you.
(1) A sign points in two directions. Take the right-hand path towards “A Capaighja”. Cross a ford and continue along the narrow path beneath the pine trees, following the river. You’ll arrive at the Capiaghja Spring.
(2) Continue uphill towards the Capiaghja Sheepfolds, from where several walking routes are accessible at this point.
(3) Turn slightly to the right, cross the river and you’ll reach the metal bridge.
(4) Return via the same route to the Sellola Bridge (S/E).
As for the elevation gain, there’s a 1-metre difference. I don’t see why you’re saying the technical data is completely made up...