simple as port starboard?

Two phases:  from the edge of the zone to the mark:  IW is only entitled to room to sail her direct course:  at the mark, IW is entitled to sail her proper course to get fastest to the next mark.

And according to Bryan Willis, OL needs to be steering a course sufficiently outside the mark to allow IW room to round it (2xBmax?), at the instant the first boat reaches the zone.

But once she is at  the mark, as long as she is taking 'mark-room to which she is entitled' she shall be exonerated under rule 18.5 for breaking rule 11, and, as long as contact does cause damage or injury, shall not be penalised under rule 14 (rule 14(b)).

I think that once at the mark, IW could bear away and 'flare' a little to create more room, but there may be a dispute about whether she was at or to the mark, and whether she bore away too far.

If there's no contact with something then a 'room' protest is hard to win.

Why?  there is no game change.

No-one is interested in how much room he 'anticipates' you need (unless you are getting into really arcane stuff about rule 14(a)).  What counts is how much room the protest committee decided you needed to sail your proper course at the mark.  If the PC are all laser sailors, then you might be stuck.

And you don't like being attacked by Topper Mums because .....?

Hmmm this gets more and more confusing.

My interpretations after sieving through books, is that you are entitled enough room when you are at the mark, to make a proper course rounding. for arguments sake wide in, tight out, which say in a laser requires 10feet of room. You cannot take anymore than these ten feet, otherwise you will have broken rule 18.4. you are required to avoid contact, so you cannot "barge" yourself some room, i.e. if the outside boat gives you only 6 foot, all you can do is take the 6 foot and protest. if contact occurs in that 6 foot you are exonerated as long as it was without intention.

I believe you can squeeze the outside boat out enough to make a proper course rounding in this example, 10 feet. but if the outside boat is having none of it, you cannot make contact with him as you are not avoiding contact rule 14a

the rule 14, Avoiding Contact, reads

a boat shall avoid contact with another boat if reasonably possible. However, a right-of-way boat or one entitled room or mark-room

(a) need not act to avoid contact until it is clear that the other boat is not keeping clear or giving room or mark-room

(b) shall not be penalized under this rule unless there is contact that causes damage or injury.

basically you can bear away or luff up, as long as the other outside boat is bearing away also i.e. their bow is pointing away from the mark, but if they are not playing ball, when you bear away to gain the room you are entitled, you cannot hit them as this is not avoiding contact and is a breach of rule 14(a).

But does Rule 14(b) not contradict rule 14(a)?? If you cannot be penalised, if you are right of way boat/entitled to mark-room, unless you cause damage or injury. so surely in a bullet proof boat like a pico rule 14(a) doesnt exist (unless heaven forbid, you injure someone) and you can barge yourself some room without being penalised?

god this is so confusing/grey its making my brain hurt thinking about it

The tactical opportunity occurs for any boats behind.

Given that OL should/could be giving more mark room than under the old rules when IW was not entitled, there is a greater likelihood of a gap for Clear astern (CA) to sail into in a safe windward position.

For OL the decision as to whether to round outside and ahead in safe leeward/lee bow position or to slow and come inside is probably shifted further in favour of slow and inside since the former will be harder to obtain.

You've not exactly understood what I meant.  At leeward marks there is often an opportunity for CA to turn inside OL, ending up in one of 3 positions:

CA of IW and CA of OL (OL and IW remain overlapped) but in a safe windward position with respect to OL.  OL suffers more in the downwind, as opposed to lee bow, dirty air from IW, and can not luff.  CA is in a passing lane.

CA of IW and overlapped with OL (OL and IW remain overlapped).  Presence of IW limits ability of OL to close the gap.  As above - CA is in a passing lane.

CA of IW and overlapped with OL (OL and IW are not overlapped).  CA is no longer "protected" by IW, and there is greater risk of OL shutting the door as described in your post.  However often OL will struggle to do so without serious detriment to her own position.

Under the new rules OL is likely to be further from the mark, increasing the oportunities for CA in each of the examples above.

OL should never have let herself get in that situation in any case. She should have luffed much higher than the mark well in advance of the zone, then born off hard just before the zone to break overlap. This assumes the overlap had been ongoing for some time. If not and IW had just established overlap just before the zone then OL should have seen her coming and, again, driven high to avoid being rolled, either taking IW with her or forcing her to the outside where she would have been buried as the new OL.

This only makes any sense if the two boats are of similar handicap. If there is a vast difference in speed then let the faster boat go and get on with your own racing. No point in an Oppie match-racing a 49er.