I'm a tall guy like you, it sucks being tall at first. It's a blessing and a curse. Regardless of how you are, next to a short guy we are always 'bigger', but standing alone we'll look smaller, while a shorter guy standing alone will look bigger. Having long limbs and a large frame means we can theoretically carry a lot of weight without looking like a condensed fridge, but the shorter guys will always pack on thickness and appear thicker far far easier with a lot less food and a lot less weights. Short guy = jacked tank. Tall guy = Long-term more appealing.
As a tall guy, got to lift heavier than the shorter guy, got to eat more than the shorter guy, etc...etc... it's a pita of work.. oh yes and need more gear/drugs too. So I just stopped caring as I'm not trying to compete. Can look much better as a physique competitor as a tall guy instead. It's easier than trying to be a monster bodybuilder. Bodybuilding is not profitable so who cares, lift, eat, juice enjoy.
Slin could definetely help, I just don't bother. It seems as soon as one starts using slin for the most part the physique goes fuck all even though it packs on size fast.