If you've got enough IC to build tanks, and enough Leadership to research both the techs (4) and the doctrines (at least 3-4) needed to use them effectively, then you've got plenty of IC and Leadership to spam 2xART (2 techs, 2 doctrines) in every division, plus one with the HQs (but you'll still need one "front line" brigade with the HQ for it to participate in combat).
You'll probably want AT in one of two divisions per Corps to deal with the Light Armor that Germany will inevitably field, but not in every division, to deal with everything else. You only REALLY need to research the Ammunition and Gun Carriage tech to boost its Piercing, the rest is nice to have, but "optional".
If I can put ART in all of Hungary's 14 starting divisions, plus all 5 HQs before the outbreak of war in '39, and also build 4 more complete divisions and a couple more Fighter units with their limited IC (30 effective IC with the various ministers and laws available), Poland should have no problem with its greater IC in building a no-frills army capable of holding the Germans for a long time at some convenient river lines or other terrain features. Pushing into Germany is asking for a LOT, however.
Your big advantage is that you already know when the war will start, possibly give or take a couple of days (the AI works on a schedule), so you can build your forces cheaply at a low state of mobilization, then mobilize a month or two before the war begins. Your initial mobilization provides a 50% cost reduction, so you can bring all of that stuff up to full strength at HALF of the cost difference between its un-mobilized strength and its full strength. Your weak point is that your troops can't start acquiring a "dug-in" bonus until war is declared, so any units on the front that are attacked immediately will not have that bonus.
Now I'm tempted to do a Polish run.
[Update - Started a Polish campaign, Normal difficulty.
Jan. 1, 1936 - Poland has significantly more Leadership and IC than I've had with a couple of games with Hungary (roughly 9 versus 7 Leadership, and somewhere around 37 versus 27 base IC), plus a LOT more starting troops and a few extra techs already researched, but I'll be facing Germany instead of the Soviets. Pumped about 4+ points of Leadership in to Espionage temporarily (10 Defensive spies first, then 10 into France and Czechoslovakia), 2 points into Diplomacy for now, half a point into Officers, and the small remainder into Research of Agriculture and Education. Set domestic spy priority to max level, and 3 pips on Counter-Espionage.
Building several ART brigades, one AT brigade, one INF brigade, and a one INT for now. After I put one ART in each division, I'll begin putting AT into one division per Corps in place of INF, and attach the spare INFs to the Corps HQs.
Jan.2 - made several trades to sell small quantities of Coal to potential friends or allies to boost Relations, a big sale of supplies to the Soviets for cash, and a smaller one to the US of A to improve Relations.
Jan. 10 - second round of small coal sales to several countries, and small supply sales to US and SU. More importantly, my Neutrality dipped under 70. Changed my Production laws from Partial Mobilization down to Full Civilian Economy. Next day, the "Prepare for War" decision was available. Activated the decision, then switched to Full Mobilization laws. The decreasing Neutrality should lower my Consumer Demand over time, as well as allow future "shenanigans".
Jan. 31 - Enough spies and Diplomats for now. Dropped Espionage down to 0.6 points, Diplomacy to around 0.2, and put all of the rest into Researching mostly Infantry weapons and doctrines. Not sure if I can afford Armor or not, but I do intend to contest the air in the East while half the German air force is tied up against the French and British. I will boost Officer Ratio drastically when I've got better modifiers to it; it just isn't worthwhile at -50%.
Jan. 20 - purchased metal and rares from those countries I sold Coal to, at lower prices due to the improved relations.
Jan. 31 - more small coal sales and metal/rare purchases. Changed domestic spy mission by placing 1 pip each into Party Support and National Unity, still with 3 pips in Counter-Espionage. Set spy mission in France to Tech theft, CZE to Counter-Espionage to rid them of any German spies who might begin lowering their NU.
Now up to around August '36. If I can lower my Neutrality enough, with the help of Germany's annexation of Austria, I'm hoping to invade and annex Czechoslovakia, which would deprive Germany of all those tasty Cores and free manpower. That will have the side effect of reducing my Neutrality to 0 and practically eliminate the need for consumer goods, and I can then remain permanently mobilized. By building all my costly ART up front at Volunteer Army and Basic Training, I can switch to 3 Year Draft and Specialist Training when I mobilize, and fill up the ranks to at least 90% at half price with highly trained recruits before I run out of Manpower. With the better recruiting laws, the Manpower and Officer pools will have bonuses, not penalties, and I'll have some additional Manpower from CZE, so hopefully I'll fill in the missing personnel well before Germany declares on me. I'm also figuring on blitzing East Prussia as soon as Germany declares war, and eliminating those isolated divisions quickly. As with the SU, pushing back doesn't solve the long-term issue, you need to remove divisions from the map. I'll see how it goes over the weekend. ]