I’ve also paid a lot of attention to CAS. To increase the 24 SF battalion cap, you would have to exceed the 480 non-SF battalion breakeven point by 20 for each additional SF battalion. Recon is pretty trash other than light tank recon for armor cheese. In combat, divisions pile in as long as the total combat width is less than or equal to the available frontage.
Don't fight in By wartime, they had some 30+ divisions that were perfect for garrison duties.