R44 Raven II POH is
available online from Robinson. Section 5.5 (Performance) contain the graph of weight / OGE Hover, Take-Off power, Nil Wind at Density Altitude.
In addition, relevant to the actual Tread topic, Section 4 contains the checks that should be done after every engine start, and the hover checks - which includes "note MAP"
Craab - you make a good point. Don't recall being taught in PPL lessons "performance planning" for the confined area flight we were going to undertake. General planning for a flight (weight & balance, performance, fuel, route and diversions, etc) but not specifically planning ahead for this. Certainly was taught - as Robbie notes - how to assess the site, check available power for OGE and descent / climb-out, and how to approach and get into the site. That is not the same thing, as you say. There is therefore room for a training improvement there.
Training did include "artifically lowered" power so that you had to decide not to go in, or once in artificially lowered margins to show what might happen you now had to get out with less power than you might have wanted. This included towering but also restrictions so tight that you could not get out - as a means to showing you how to take responsibility for stopping and rethinking, rather than pressing on until you hit a tree.
I thought (still do) that the technical training was good and it left me with with this. The site we used in training for confined area was very (by my standards) tight. When first shown it from above, my reaction was "I appreciate the skills and training, but I am never going into a site like that when I have my license". I have stuck to that decision ever since, and take the view that "just because I can" doesn't mean that I should. There is, in reality, no justification for me to act otherwise as I only fly for pleasure. I do use these techniques - icluding OGE hover and descent into a lawn surrounded by Scots Pine trees, but the space is more than 3x larger than my old training area.
I would add; some years after getting my PPL the airfield stopped the use of that confined site and instead provided one surrounded by low bushes & shrubs and actually open on one side. Nothing like as challenging, and though technically "safer" to learn in I don't think it provides as good a training experience. Doing annual LPCs at that field, using that site is pretty much a non-event to me, and I think the risk is that you don't see the value of making all the right checks and asking the right questions as then you land on something that is "less difficult" than some of the Heli Pads provided on the airfield (close buildings giving recirculation issues, for example).