So the build around these 2 for DPS is basically to use VT for the move speed and 30% bonus dmg andstack that with another SI which also adds damage. In Cav scout it is ST (steel sabre) and with Platoon leader, it is IS (instructor) aura. When stacking these bonuses, especially for Cav scout you realise you do similar attack speed to an auto rifleman when you have a Styner, but with a base damage that is very much higher. All without using any energy for added attack speed or damage.
The good point about using cav scout is that you can flare AND bino, as opposed to PL who can only bino. Furthermore, Cav scout's inherent faster attack speed is much better(20% faster. 0.25 vs 0.3) than a 6% aura from IS. Although PL does have laser pointer,It doesnt help much against smaller zombies. I've seen around 300dmg crits with these builds and they do good dmg to rival the Autorifles. MCR for cav scout soaks up too much ammo even with a mag extender so a styner is actually more advisable and economical. PL's additional damage from concentration (lvl 4 leadership unlock) and the IS aura will both give your team a boost as well to reload times. That said, PL reload times will be VERY short which overall compensates the atk speed of the cav scout as he has less downtime reloading compared with a cav scout.
Cav scout has a lovely 0.25s base shot time (4 hits per sec)
+dmg= 30% (VT) + ~20% base (ST, wiki doesnt say

PL Aura stacking with IS is like having QT+VT already although base atk speed is 0.3s, so it compensates a bit.
+dmg = 30% (VT) + 20% (aura) + 6%atk speed (IS) + 25% concentration skill on lvl 4 aura
- Cav scout: VT+ST
gives around 65-73base damage AT START. no guns lvl 1
Build: lvl 1, 2 soldier skills (For burst fire)
3 cav scout skills/marksmanship alternate levels. or if your team requires motion sensor then rush it. dont bother getting lvl 4 for CFF. focus on marksmanship or maxing soldier skills.
Since VT gives move speed, you dont have to worry about being slow before getting lvl 1 scout skills and can go direct for burst fire. - Platoon Leader VT+IS
Also gives around 65-74 damage at the start.
Same as cav scout, lvl 1, 2 = soldier skills 2,
lvl 3 = marksmanship if you find a gun,
or go for aura. Then max out marksmanship and soldier skills.
Essential: Choice of guns: 1. SOF-AR obviously. If not go for the Styner(VT cancels move speed penalty) or MCR instead of M5 or HK42. The MCR is VERY nice, but i wouldnt take it if i didnt have a magazine extender.
Magazine extender(!!) , flashlight, scope, AA, AP/DU rounds.
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Soooo why not IS+VT on cav scout? Well yeah you should do that if you havent unlocked ST, but it isnt as good dps.