It depends, do you want to play Iron Hands, or Codex-adherent Robo-Vulcans?
To be serious though, no judgement, if you like the idea of a Codex-adherent chapter with slightly better vehicles and more bionics, the nuHands in the latest codex work fine and you can just make a Codex company with the "clan" markings.
However, prior to the most recent lists, where they were neutered so they could be easily "consolidated", they were a very different and
IMO far superior beast.
They were, if anything, less Codex-adherent than the Space Wolves, with each Clan Company being a fairly self-sufficient and self-contained entity with its own mobile fortress, armoury, and specialist ranks(librarians and so forth). Chaplains and Techmarines were combined into a single role, Iron Fathers, and Clan Companies could be led by one of them, by a Clan Commander, or even by an ancient Dreadnought. They revered Terminator armour and deployed it to those in leadership positions, even down to the level of squad Sergeants, sometimes if a Clan had enough suits also a bodyguard unit for the Commander. Regards the numbers you asked about; Clan Companies varied in size, but
here is an image from the pre-rewrite novel Wrath of Iron depicting Clan Raukaan, which should serve as a rough guide.
There was no Chapter Master helping them rediscover their feely-weelies because they weren't idiotic self-hating robots, rather they were ruled by a cold, unrelenting hatred of weakness and ruthless pragmatism, and they put the blame for Ferrus'
disappearance(because at that stage
BL and
FW hadn't decided to make Ferrus into the
HH series punching bag yet) where it belonged - on the backs of the cowardly Raven Guard and Salamanders who fled the field rather than supporting Ferrus' charge, supporting their sire's reasoning that the destruction of all three of their Legions would have been a price worth paying to kill the leaders of the Heresy and cripple their Legions.
They used to be a proud chapter with their own history, organisation, and character, and now they're the only recorded chapter who openly criticise their own Primarch and strive NOT to be like him. You choose.