Kurapika said he wanted to be Reinforcement and was disappointed that he turned out to be Materialize. Assuming he still keeps his special ability, what would happen if he was indeed Reinforcement normal and Specialize while in Scarlet Eyes? Well, his physical attack/defense would increase. His self healing ability will increase greatly (and it's already pretty crazy to begin with). Judgment Chain is Emission based so that will go up in power too, so maybe he can use it in mid combat. Chain Jail won't be as strong, but is it really necessary? All he has to do is knock a guy out and then use Judgment Chain and it's trivial to duplicate Chain Jail's effect or better. With increased physical strength and increased self recovery, I don't think anybody from the Spiders can possibly fight him 1 on 1. Ubogin might still be stronger but he appears to have no self-recovery ability, so Kurapika will eventually outlast him. Most of the Spiders have ability geared toward just doing damage, but that'd be useless against his recovery techniques. Kurapika is obviously as smart as any of the characters we've seen, so it's unlikely someone can trick him.
I guess it's a good thing he wasn't Reinforcement or the story wouldn't be nearly as interesting. Between upgraded healing, physical ability, and upgraded Judgment Chain, he wouldn't even need to take additional risks to begin with.
He'd basically be a brawler type and then we won't see the chains. Still it don't matter since he can use 100% of every school. He can use the chains with 100% reinforcement or be like Gon but is able to materialize a chain easily to whip ass.
If he was reinforcement, he would be dead by now. His "specialization" is the only reason why he could stand up against the ryodan ... without it, he is just a talented rookie.
I'm assuming he can still turn into Specialization while in Scarlet Eyes since that seems to be something based on heritage.
He'd still develop self-healing abilities because that's simply a good idea. It might not take the form of a chain but he'll still have a comparable ability.
He will also develop something like Judgment Chain since that's clearly an ability he wanted to use against Spiders. It might look differently but it'll still do the same function.
Chain Jail might go away since he'd have no reason to try to merely contain his enemy if he can overpower them. Chain Jail isn't useful in 1 versus many anyway (it ties up his primary hand so he'd be completely vulnerable to anyone else), and if he's strong enough to beat someone physically 1 on 1 he wouldn't need Chain Jail to begin with. Judgment Chain is actually better at making sure someone stays incapaciated after you beat them.