What hull would go best with railgun ?

No, wasp is better than hornet in almost every way.

dictators height is a major advantage, but speed lets it down. Even though it has tough armour, i am not over-all keen on the looks

so, with a railgun, what would offer the best railgun gameplay

don't know- hornet too little hp. viking stats are good overall though

For me I use Railgun M1 paired up with Hornet M1. Actually, I like both Hornet and Wasp. I'm fine with Viking and Hunter as their armour is good. However, they are a little too slow for speed and is not a very good choice if a tanker chooses to play CTF mode and wishes to capture a flag.

But no one can really get the most perfect answer, as it depends on a tanker's liking and he or she should decide for himself/herself.

hornet, it has better maneuverability than wasp and if youre  

a tank guy, then use titan or mamoth

In my opinion hunter is the best hull with railgun and I have reasoning.. railgun is a long range gun and should be used for camping from further distances and peaking from walls to shoot. Hunter may not be as good as the wasp at peaking as this as the turret is towards the middle of the tank but is very capable of doing so. What is good about the hunter is that it can take a beating and is the faster of the medium tanks making it good for most situations. Another benefit of the hunter is the special, the shock... the shock is good for the railgun as it is can stop up close weapons from firing and freezes them allowing you to retreat. This special can be triggering for druggers as the special takes any affects your enemy has away. If you want more speed wasp is the best hull as it nearly has the same health as the hornet and is more agile and swift while turning. The main reason this tank is the best light tank for railgun is because of the turret placement making it the best tank for peaking, the speed of the tank also helps with this.