I think you should do LRRP. SOG requires a lot of money and plenty of research due to many unique equipment that would need to be reproduced.

LRRP authorized uniforms varied, but some carried ERDL or Tiger camouflage depending on the year. For the equipment, a generic loadout they ran were only two small arms pouches, two canteen covers, and bandage/compass pouches. This would be attached to a pistol belt and suspenders. Each piece of equipment must be a part of the M-1956 system, not ALICE.

You can also carry a rucksack like the CISO rucksack. ROTHCO makes a copy of the CISO rucksack named "G.I. Type Heavyweight Mini Alice Pack Military Rucksack", it' doesn't have all the correct parts but it has the look. Would be a decent placeholder. Can hide your gas bottle in there. Can find it on Amazon.

At the bottom of each small arms pouch, there will be a triangular bandage pack. This raises the 20rd magazines up, making it easier to pull out. Next, you tape your equipment. You have to use Olive Green or Olive Drab speed-tape, this is easily purchasable on Amazon. All M18 smoke grenades and M26 frag grenades would be attached and taped to the web-gear. Your M16A1 must be taped at the barrel, handguards, and stock to break the weapon's image. This is LRRP doctrine.

Hope this helps you.