Sam (and Ben), I appreciate the spirit of your response to the question about Bastions, but I'm not sure that it answers the specific questions I asked. I get that we shouldn't "model for advantage", but I'm asking for more specific parameters on what counts as modeling for advantage and what doesn't.
If the book actually said, "Bastions have a total of 12 firepoints, 3 per side, and they are 4" up the side of the thing", then clearly putting the firepoints anywhere else would be modelling for advantage and shouldn't be done.
On the other hand, if the book said "It's up to you how many access points and firepoints the bastion should have, as long as it's not more than 10 of each, and they can be anywhere on the model", then clearly putting these things in an optimal spot would be fine.
However, what we have is sort of in between. The book sort of hints that bastions can be customized (in the manner of an Aegis defense line), but doesn't give any guidelines. So I think the 40k community should forge a more specific understanding about HOW customizeable these things are (if at all). If the answer is, "it needs to have everything in pretty much the same spot as it is on the Imperial Bastion model", then when I'm scratch building my Haunted Tomb, that's what I'll keep in mind. If more freedom is allowed, since I'm scratch building the thing anyway, I might as well put the features in more effective locations.
So - the specific questions that I don't feel like have been sufficiently answered were (and I don't expect a "snap ruling", just pointing this out as stuff that needs specific answers eventually):
- How close do the size and shape of a homebuilt bastion need to be to the imperial model?
- Do the heavy bolters actually HAVE to be arranged in a perfect square?
- Can we make Bastions with a different layout of access points?
- Can we make Bastions with a different layout of fire points?
- What's the arc of fire on those heavy bolters? I'm assuming it's sponsons meaning basically, if the heavy bolter can see a target it can fire at it?