Let me suggest some:
For the Captain Player
-Three Riflemen
-Ambulance
-Captain
-Pack Howitzer
-Stuart Light Tank
-AT Gun
-Major
-M8A1 Howitzer Motor Carriage
-AT gun
-Sherman
-Jacksons
Aim for these armies. Try to make good decisions based on what you see. These are basically doctrine non-specific but you can change them based on the doctrine you are going.
I actually wrote my "In Before the Blitz" guide for Airborne players who want to get a fast Captain. It is basically the build above but in team games I always suggest a Pack Howitzer if you go fast Captain. They're pretty nice and the powerful early game of the US forces means you can afford it.
I can't watch the replays because im at work but i can tell you that a properly microed stuart is probably as valuable if not more than a jackson, and its half the price.
I can second this for airborne, proper micro of the stuart and using its 3 shot blind/stun ability with the captain backing it up can annihilate early light armor without taking any direct damage from the armor(watch for AT guns and AT inf though). the stuart also blends effectively into the late game better than the flaktrack, especially on 2v2 maps where their are a lot of large open maps and usually german turtling armor.
mid game
before the heavy german armor comes out, use the stuart to back up 1 rifleman squad that is harassing the lesser defended areas, this will force the germans to send some kind of AT, keep it far enough back that the enemy can't see it when they hit your riflemen, but when they do, bring it up and micro any threats then fall back, rinse and repeat. You can effectively lock down the weak areas with proper riflemen placement and stuart support. And if you can afford a airborne x2 1919 squad GG to any light counters your way.(if an MG/AT gun comes, smoke the MG and push your airborne for a flank(you can also use this tactic to demo charge bunkers with airborne). Don't push your stuart if a light armor/infantry comes though, just put some shots into it, push it back and hold the line, your stuart presence is more valuable as a threat than actually trying to get a kill with it, especially if you are already holding both fuels.(you'll out tech them nullifying the light armor once you can get a sherman or jackson up for support)
late game
once the heavy armor starts rolling, shift the stuart back to your strong front and keep it behind your AT and jackson. Once you see an armor push, your .50/howitzer/sherman .50 should lock down any infantry, use the stuart to flank and stun shot the heavy armor, push a riflemen squad up to AT nade it, flank with your sherman and let your jackson/AT guns tear it apart with armor piercing ability rounds from afar. A very effective thing to get good at with proper armor micro is to use ctrl-(1-9) to set your unit hotkeys, i usually set artillery (1) stuart (2), sherman (3), jackson (4),(always set the same starting out for muscle memory) this allows you to quickly cycle and position them. Another method is put two or more shermans in (2) then hit "tab" to cycle in the group, this way you dont have to punch 1-6 to get all your units.
Once the german armor is taken out, pop smoke on any hurt shermans, shermans can pop smoke but they have to stop moving to do so(if you have 2, shoot the smoke from the healthy one to protect the hurt one) howitzers also can provide smoke for your retreating stuart(fire this ahead of time) and riflemen also smoke. It will take a while to get good at but if you can, it can be extremely punishing to an over zealous german. Once you force the retreat push your line up quickly, lock down your new area close to their HQ. At this point you pose a dangerous threat to their main base and are probably in howitzer range of it, either forcing the other player to shift his armor(weakening your friends front) to halt you or suffer the base rape.
tips
hotkeying your stuart/captain in mid game is also advised.
always right click and drag the direction you want the armor to face.
shift click specific routes for tough terrain.
Try to get directly behind the enemy armor with the stuart at pointblank range for three reasons, one, if your round penetrates it stunts(immobilization), two, you can use your pointblank ability to do more damage, and three, you can block the armor from retreat if your riflemen can't get an AT nade in. once your 3 shot ability is done get out of there, the stuart has done its job.(howi/riflemen smoke the retreat path before the Stuart gets behind the armor).
If you see any armor push you with an HMG/AT gun firing behind it, always start with your artillery at hotkey (1) to blind it with smoke before microing your armor. howitzer smoke is more effective in large attacks to blind the enemy HMGs/AT guns than direct firing HE. if you can stuart stun and cut off its infantry AT/support with smoke from your hopefully large arsenal of smoke machines you'll decimate the armor then be able to mop up the remaining infantry.
When retreating your stuart, usually moving to the flanks of the engagement is the safest, an easy minimap click will send it on its way without you have to worry about it, i usually send it far back behind my lines till i can repair it. If you have good situational awareness you can also send it behind the smoked out AT guns to make quick work. Unless you're playing really good players they probably wont be able to to notice it to turn their guns one you with their panther/tiger getting annihilated.