Penal builds vs Light vehicles

I'm having a lot of troubles dealing with light vehicles with my current penal build

Base CE > CE > T1 > Penal > M3 > Penal > Penal

Back teching is not always viable due to the manpower tax of maintaining expensive squads on the field (without RA bonuses) limits the chances of getting a Zis ASAP. Also the Zis can only stop vehicle plays but not finish the job due to its slow rate of fire.

T70s are always late against cheaper vehicles like the 222 or the flametrack

Su76s while being the best option due their awasome scaling, are also quite far away against the cheaper ostheer light vehicles.

The only adequate AT option I've found are guards as they just use manpower and the ammo for the Dp28 is always available. It doesn't slow your tech and can also fight infantry though they still have problems agains the flametrack (they need to stand still to fire the PTRS) and the flaktrack (Supression allows it to lower your firing rate, has smoke to cancel your button and its damage output its not a joke).

Mines are also usefull if you manage to rout the oponent and plant them agresively or to punish dives.

This however basicly locks me out of any doctrine without guards, which is quite limiting (and boring)

So, how you deal with light vehicles when going, lets say, shock troops doctrines?

If you keep your m3a1 alive it does a great job with a single penal squad in the back that is now allowed to fire at all times, not only when standing still. You will not win against the 222 headon but you could get some shots from max range and if your enemy is slow at reacting use the overdrive to close in throw a satchel and try to get the hell out of there (satchel does 240/320 damage so be sure it will finish the vehicle).
The su76 has its uses if you play it in combination with the t70 like the p2 and puma combination and it works best if your enemy played no light vehicles but somehow got to (or near) a p4. I wouldn't recommend playing it against double Atguns or Pgrens with schrecks and sprint and it is best used if you intend not to tech t4 otherwise the t2 backtech after a t70 is usually better (not if the enemy uses mulitple stukas or other indirect options).
If you prefer elite infantry above penals you might try playing 2 penals only and stack some manpower or get early healing and focus your micro more on the clowncar but that is up to you.
The m42 is also quite fun to play and available in one shock troop doctrine that even allows to play the kv2 and maybe to skip the t4 building.

Generally I think you have to options to deal with light vehicles. You can opt for a Penal with a PTRS package in the M3 (risky) or you can instead focus on going for two squads or Guardsmen and trying to get a T-70 as quickly as possible. Don't go for the M3 if you go for two Guard's squads. While Penals in the M3 with PTRS are decent against LV's I don't like how poor they are against STG Volks. So I generally go for two engineers, 3 penals, into two squads of Guards with DP's. My build order is the following for the early game, Base CE - CE - Tier 1 - Penal - Penal - Penal - Field Infirmary - Guard - Guard - Tier 3 - T-70. After the T-70 I generally will backtech Tier 2 for a Zis-Gun to deal with more than 1 LV and then push for Tier 4 armor. You can also go Urban Defense doctrine for Shocks and M42's. With that build I typically will get 1-2 M42's instead of a 2nd squad of Guardsmen. Most people go for the M3 because it has a large amount of shock value if well micro'd but against a smart player you will see a Rak after the 3rd Squad of Volks and they will lay multiple mines making it difficult to sweep all of them. Plus if you go for a Flamer and Sweeper you will not have the munitions to get DP's and PTRS on your Penals and Guards. (Although a lot of what I said counters OKW)

You're on the right track here buddy.

So I either go 4 penals without PTRS into Guards so you have some solid AI capabilities and then Guards to back you.

OR

I got 4 Penals, 1 with PTRS, then 2 PTRS while going a doctrine that has Shocks. Shocks are very good now, and pairing them with T1 soviets is just incredibly fun. It also gives you a very easy way to deal with machine guns as Penals are pretty bad vs any kind of suppression and Shocks give you that smoke grenade. Most opponents will just retreat the MG and not risk being satchel or overwhelmed.

I often throw the M5 in quite a bit, I was dueling a P4 the other day from medium cover from a crater which is important because in craters you can spread out more so the P4's not as good given it has excellent AI on bunched up squads. He couldn't come near me, and got frustrated enough that I caught him with a satchel and RIP p4.

But I get this is more about the Flammerhalf track or even the Scout car. It's going to be a lot of positioning, baiting until you get the su76 or t70 out. A good player wont let their lights die to PTRS's.

Hope this helps, I thorougly enjoy Penals and Shocks right now. Guards are fun too, but Shocks are just so good right now.

against WM you can get halftracks to deal with anything they have.

The HT .50 cal is very strong vs flame track and you can use PTRS vs 222, also HT can reinforce on the field making your offensive much stronger.