It seems that determining how my company RTOW charts have been devised is one matter, as is the identification of any other obstacles beyond the surveyed area.
You should have some guidance as to how things are done etc in whatever general information is included in your Ops Manual performance section ? Otherwise, why not just ask the ops eng boss for the answers ? If he/she doesn't want to talk then I'd be concerned.
The rest of your post presumes that the aircraft is WAT limited in all segments regardless and this doesn't apply usually. While your calculations might give you a feel for the conservative side of things, it probably doesn't provide much useful data. You really need to plug real numbers into the AFM. I presume that you have access to an AFM ? - that doesn't necessarily follow as your fleet may carry the ops manual in lieu of the AFM per regulatory concession which is typical for airline operators.
First segment may also come into the calculation for your Model ?
there is an MSA of 3,000' and we use an acceleration altitude of 1,700' (which is 400 and something feet AGL in this case).
Generally MSA is a bit of a crude sledgehammer when looking at takeoff flight paths. What is required is to match the AFM profile to the obstacle splay profile
there is no way we will reach 3,000' within the 25nm of the MSA.
Nor is there a necessary requirement to do so .. providing that the takeoff net obstacle clearances are being met.
need to manoeuvre within the MSA until either the MSA or LSALT was reached. Which would entail very small bank angles to preserve any of that 53 fpm available.
Again, the pilot would need to know the detailed obstacle environment. This is something that the ops eng folk should be providing for you in the case of a critical aerodrome.
Having said that, there have been more than a few cases in the past where I have upset the locals by climbing in the circuit to get an appropriate height prior to setting course, especially at night, if I haven't got the obstacle data to my satisfaction.
Is that how I should look at it?
Sounds like you are a pragmatic and conservative chap - what now counts is for you to find out what the operator is giving you in the way of information and, if you aren't happy with it, pursue it with the ops eng folk.