Presumably, if the peripheral USA had such details, (necessarily from a German source?), then a Germany genuinely concerned to avoid war had already transmitted them to the only party they directly concerned - Poland?
Also, (I may have missed this in weight of material on this thread), when did Germany formally present the UK and France with their hard copies of the so-called Marienwerder Proposals?
The German Government did not officially present a copy of the Marienwerder Proposals to the Polish Government, since the latter refused to receive any proposals at all.
The German intention was to present the proposals to a Polish plenipotentiary at a meeting in Berlin on 30 August. However, the Polish Government declined to send a plenipotentiary.
The next chance for the proposals to be presented directly to a representative of the Polish Government was at the meeting between Ribbentrop and Polish ambassador Lipski on the evening of 31 August, a meeting requested by LIpski on the instructions of the Polish Government.
However, Lipski had been specifically ordered by the Polish Government not to enter into any negotiations, nor to receive any official German proposals. The only reason the Polish Government instructed its ambassador to meet Ribbentrop was because the British Government had asked to make contact with the German Government.
The German Government was well aware of the Polish Government's orders to LIpski, since they had been intercepted by Göring's wiretapping operation, the so-called Forschungsamt. Accordingly, the Germans knew that Poland would refuse to receive an official copy of the proposals, and that the meeting requested by LIpski was just a sham to give the appearance of acceding to a British request (which might itself have been a sham, although that is not certain).
Despite the Polish Government's refusal to receive the proposals officially, The German Government did not withhold them, since it could be taken for granted that the Polish Government would receive them unofficially from the British.
The German Government did not make an official presentation of the proposals to the British Government, since they were a matter for negotiation between Germany and Poland. However, it made the content of them known to the British representatives in Berlin at the earliest possible opportunity, which was when Ambassador Henderson came to see Ribbentrop shortly before midnight on 30 August.
It should be pointed out that the German Government launched its diplomatic initiative on 29 August, officially requesting the British Government to arrange for a Polish plenipotentiary to arrive in Berlin by midnight on the next day, ie allowing more than 24 hours, for the purpose of negotiating on the basis of official proposals that would be presented to that plenipotentiary.
However, the British Government did not send its negative response to Ambassador Henderson until the next day, and delayed authorising him to present that negative response to the German Government until late in the evening of the 30th. The British action gives the appearance of wanting to delay giving its negative response until after the time allowed for the arrival of the Polish plenipotentiary had expired.
Despite those apparent British delaying tactics (which were none of Ambassador Henderson's doing), the German Government made two attempts to convey the content of the proposals to the Britisah representatives.
First, Ribbentrop read out the entire set of proposals to Ambassador Henderson at their meeting at midnight on 30 August, in the German original, speaking at a normal speed and adding explanations at various points. The German official interpreter, Schmidt, was present at the meeting, and was ready to translate what Ribbentrop had read, at dictation speed so that Henderson could write down the translation.
If Henderson failed to understand the proposals in their entirety, it was because of his insufficient command of German and his failure, perhaps due to his unwillingness to admit that insufficiency, to request a dictated translation.
Secondly, shorty after the above meeting, Göring gave Dahlerus a written copy of the proposals, which Dahlerus read out over the phone to the British Embassy, where Ogilvie-Forbes copied them down and then forwarded copies to various recipients, including the Polish and United States diplomatic representatives, who had received them by 4:00 Am on 31 August at the latest.
The bottom line is that, by the time the Polish Government on the morning of 31 August instructed Ambassador LIpski not to receive officially any German proposals, or to enter into negotiations, it must have been well aware of the content of those proposals. The Polish Government, despite an official request from the British Government to enter into talks, remained totally intransigent and unwilling to enter into any negotiations whatever on the issues in dispute with Germany, despite the balanced nature of the German proposals.
Sid, the above is my intepretation of the course of events. You are entirely at liberty to accept or reject that interpretation, as your fancy takes you. But whatever you decide, be happy!