If you were Commander-in-Chief East Front after Zitadelle, Russians attacking on the whole East Front, how would you organize AT defence? Lots of tanks, lots of AT guns, lots of Sturmgeschutzes, lots of Panzerfausts- and schrecks, lots of mines or a mixture of these? Even Rommel, whose victories were won by tanks and mobility, said to Hitler in July 1943: "The main defence against tank is the AT gun... If we can give German infantry divisions first fifty, then a hundred, then two hundred 75mm AT guns each and install them in carefully prepared positions, covered by large minefields, we shall be able to halt the Russians... There is not even a slightest hope of our keeping pace with enemy in production of tanks, but we certainly can in AT guns...
The enemy is mobile. AT guns will be lost. I'd go for SP guns, like the Germans actually did out of necessity and lack of options at the end of the war. In practice you'd probably need a little of everything; AT guns for defensive positions, SP tank destroyers for long-range engagements and mobile tank destroying forces, Panzerfausts and Panzerschrecks for infantry close defense.
I agree with the above. To rely on AT guns too much is a recipe for disaster. You can stop or hurt an enemy with AT guns such as they did at Kursk but they cannot persue an enemy as well as mobile forces. You have to use the hammer and anvil strategy. In Poland and Germany AT guns were vulnerable to artillery though. All things being equal, Stugs and medium tanks should be relied on more than AT guns. AT guns and infantry are good for defence but they need the hammer of mobility to gain the initiative and the victory.
Unless your in a static defense warfare with cleardrawn (WW1 style) it is always better to have assault guns and stugs than paks.
I will built as many tank destroyers as possible, focusing on the Jagdpanzer-IV (plenty of Pz-IV chassis) and Sturmg with the long-barrel 75mm guns. Or you can simply build more tanks, hate to be stubborn but I always thought that the best anti-tank weapon is another tank. You can't rely on airplanes to support you all the time.
