Ok, so, I don't know if I can vote, but I'll try to give arguments and answer questions.
Allen can also fight while badly injured, his willpower is what gives him immortality type 2 and regeneration (overtime and not combat applicable), as he can keep on fighting while contanstly riddled by weapons able to injure him and survive
this (even though it likely incapacitated him).
The Gigant upscales from 4.7 to an unknown degree, as it is much more durable than Allen himself, and is able to totally crush tanks just by stepping on them.
The Gigant isn't exceptionally agile, but it can move normally, jump around and perform charges by sliding at "high" speed (there are some gifs on the tabber, if you want to check them).
While on board of the Gigant, Allen generally fights from distance, shooting bombs, missiles and charging only in some occasions, he doesn't go for physical combat. The same applies to him outside of the robot, despite his habit to laugh at the enemy, he's
very careful at moving and dodging the enemy fire, not engaging in physical combat very often (he also is around 9-B with physical strikes and his knife).
About LS, I'm not sure, I never tried to request a calc for the Gigant, I wouldn't even know what to use a feat (maybe crushing tanks with a step? Not sure). Class 5 comes from him being at least superior to a single soldier, two of which can lift a 7 tons tank.
Also keep in mind that intelligence is a factor, Allen has fought in at least three wars and is the most skilled soldier of his army.