Well after the weekend voting, Engine A clearly won the Poll...
Engine A: 42 votes (84%)
Engine B: 2 votes (4%)
Engine C: 5 Votes (10%)
However a few comments made on a TMP thread and the FOD made sense to me, so I shall be remodelling Engine A to shorten it somewhat and add the style of the thrust nozzles from engine C to it.
MOUNTING THE ENGINES
I bought a handfull of concentric rings from EMA Model Supplies (an Architects and professional model makers suppliers with a great range of pre-machines basic shapes). These rings are a nice tight interference fit and, with a little sanding, two of them make the ideal mount for locating the command unit to the main hull.
Then by happy accident I happened to notice that the larger of the rings is just a little larger than plastic gear bought for another project from Maplin. Inspiration struck, and with a small piece of plastic semicircular rod inside the ring, the gear locates nicely and is unable to rotate! Just glue the engine mount to the main hull, and the gear to the engine and as the gear has 20 teeth, this gives me 20 posable locations for the engines! So they can be individually posed and also lined up. A little surface detailing of the engine mounts and you have the pictures below.
I shall drill 6mm holes through the centre of the engine mounts and the gear to allow for small magnets to be glued in place, ensuring the engines stay in place.
Note the forward engine mounts are wider than the rear to try and prevent the rear engines from sitting immediately behind the thrusters on the front.