This is my approach to to this issue:
http://magnificate.deviantart.com/art/Map-Survey-Mk-II-161680812
Grey colour means exactly the same as red colour ("Keep out!").
Various tints of grey represent independent Lithuania and independent states (instead of just parts of the Soviet Union) of Belarus and Ukraine:
My most important criteria for each region:
Priority 1:
0, 1, 7, 8, 28, 29, 26, 25, 24, south-western part of 9 - ethnic, cultural and historical
4, 5 - ethnic, industrial and distant history
11, 12 - ethnic, access to the sea and historical
37 - cultural, historical (Lwow) and ethnic
10 - access to the sea, defensive (Vistula line, fortress Grudziadz/Graudenz), ethnic and historical
27 - defensive (fortress Brest) and ethnic
Priority 2:
3 - ethnic, industrial (
http://www.okd.cz/en/coal-mining/ostrava-karvina-coal-basin) and historical
34, 33, southern parts of 22 & 32 - cultural, ethnic (in part of this area native Polish speakers were majority, in the other part they were large portion), historical*
16 - natural defensive qualities (area of Masuria would be an easy to defend northern border of Poland), ethnic (native Polish speakers were majority in southern East Prussia, which had been an object of Polish colonization since 14th century - see this German map from 1907 made by Paul Langhans -
http://pl.wikipedia.org/w/index.php...russia_1907.jpeg&filetimestamp=20090425165331)
41 - industry and natural resources (particularly the Boryslav-Drohobych Oil-Gas Industrial Area)
9 - shape of border and defensive (Notec/Netze river, Vistula river, Bydgoszcz/Bromberg bridgehead)
Priority 3:
35, 39 - defensive (Pripet Marshes) and majority of "nationally unconscious" population ("locals" from Polesie) who had nothing against Polish rules**
36 - shape of border (if Poland has got 35 & 39), defensive, significant Polish minority**
15 - ethnic (large percentage of Polish population) and defensive
13 (southern part) - ethnic (large percentage of Polish population)
Maybe... :
17, 14 - Danzig & East Prussia - these 2 "enclaves" surrounded by Poland & Lithuania - were the hot spots in Polish-German relations during entire interwar period, were the pretext for Hitler to invade Poland, and enabled Germany to encircle Poland from 3 sides in 1939 and invade deep Polish rears from East Prussia. Without these areas being German (but for example being partly Polish, partly Lithuanian) it would be much easier to defend Poland against Nazi Germany. With East Prussia being German, the issue of "Polish Corridor" would always be a hot spot in Polish-German relations and thus a threat for Polish territorial integrity and independence. Since Poland absolutely needed the Corridor (= access to the Sea), it should have exploited any opportunity to deprive Germany of East Prussia, even though such opportunity was unlikely to happen. Danzig was also very important for Polish economy (it had been important for Polish economy yet since 15th century). Without Danzig and after German economic boycott of Poland, Poland had to build Gdynia from scratch.
Notes:
*As for 22 - northern part of region 22 (including Wilno / Vilnius) was left for Lithuania, despite its ethnic Polish majority, for political-diplomatic & historical reasons.
I would like post-1918 Poland to build good and friendly relations with Lithuania. That's why Vilnius should remain in Lithuania.
**In case if Poland doesn't get 35, 36 and 39 - I give 39 and 35 to Belarus (maybe except for most southern parts) and 36 to Ukraine.
), but a bit eastwards it could have been. The cities of Bromberg/Bydgoszcz, Birnbaum/Międzychód, Lissa/Lesno, Rawitsch/Ravicz, Konitz/Chojnice were all clearly of German majority and near enough to be the OTL border... I mean, it would (except for Bromberg/Bydgoszcz) be no great chances, but due to the fact that such territories did end up Polish despite their clear majorities let the border not really appear as a fair compromise to me. Oh, and then theres Danzig/Gdansk, of course...
