Meh.. the Hs129 was a 1940 design that, through a quirk in the system surrounding it and the needs of the time, was kept into production almost unchanged until 1944. A very small number were made, even with such a long production run. Most had French-built engines, so the production was no strain on the limited engine production the Germans had.
Further, it was too severely underpowered, even without the one load that would be useful in AH. The big tank busting gun. WITH that gun it could barely fly a few thousand feet off the ground.
The first model carried 2x 20mm, 2x 7mm, and a whopping load of 4x50kg under the center.
A Bf109E-4 could boast the same.
The later models weren't much better. Minor changes with fuel systems, radio masts, etc.
The only real differences were the giant guns strapped under the middle. They started with the Mk101 30mm. This was eventually replaced with the Mk103. The ammo was the same but it fired faster. Then because in 1942 these weren't as effective against Soviet tanks, they started trying larger guns. They tried the big Bk3.7, same as on the Ju-87. It carried more ammo but very few ever received this. Instead they then tried the PAK 40, a 7.5cm gun in a gigantic pod. It was almost suicidal to try flying the aircraft, let alone attacking anything with that weight onboard. However only about 25 were built before production was finally shut down. How many ever saw combat is debatable.
In short, it was a flop of a ride. Even in 1940. The design remained almost unchanged until 1944, with no performance gains. The 30mm guns wouldn't do much damage to half the tanks in AH currently, and the bigger guns almost never saw combat/production so they wouldn't be valid in AH.
No need, no use, no benefit. Why add a Hs129?
