captain_jeeves, hi there. I was away for quite a while and couldn't expect the subject to be brought up again. Meanwhile we use LPC octopus software for both take off and landing performance including go around which makes it much more easier to have an idea about your performance. Despite the fact that its possible to have very accurate take off performance calculation with actual data and prevailing conditions including manual insertion of the most limited close in obstacle (the reason why in most cases we fly special EOSID) the SOP does stipulate the necessity to follow special EOSID in IMC in any case. In the example before we tried max TOW possible and didn't clear the obstacle but after insertion on the obstacle in to the take off calculation module the RTOW was limited to 210 tons A332 taking off with, one would clear the obstacle as required. In order not to have an unpleasant discussion with the lawyer better just fly EOSID. None the less its essential to have an idea about your aircraft performance in places like CDG where the simultaneous parallel RWY operation is in use and special EOSID tells you to turn in to the active RWY not a very brilliant idea though.
Regarding the go around its determined using the same software for the actual landing performance required including go around climb out gradient for normal ops 2.1% for CAT III 2.5% which tells you according to your landing data if you are limited or not. As general guideline if the landing weight is above max landing weight follow EOSID if below follow go around.
Cheers.