Heya Mate.
Try 717's with a Bontrager Big earl on the front. Its a 2.35 bit its a hell of a lot lighter than the maxxis you've got (a lot better too IMHO tried and tested both)
Or if you want somthing wider which i recommened for that size tyre try an EX729, heavier but wider.
If you build that with your king hub it'll be indestructable.
Just use silver spokes!! You could go plain guage, however you'll find that paying more for a double butted spoke (built right by a good builder) will be stronger, lighter and more durable.
Definately get a new tyre though, they're really heavy. That'll make more of a difference rather than weakening the bike by getting a light rim.
You have to think of rolling weight ect.
I hope that has helped. I'm new to the forum so not sure if you can PM but if you need anyhelp contact me. 🙂