the reason why dirt bikes and dualsport bikes use spoked wheel is because terrain can be rough and there will be lot of flying/bouncing so tubeless tires won't fare very well. That's why only sport bikes & "fat boy" cruisers use tubeless tires.
For tubed tire, the repair will suck bad because you can't just pull the nail out and then plug the hole like tubeless tires. My Metzeler Tourance tires are extremely stiff so forget about performing emergency road repair.
Maybe what I can do is cough up some $$$ for this one -
TyreShield. Motorcycle magazine has rated it as 4.5/5 and I have read dozens of good reviews about it in forum.
I have heard of tubed-to-tubeless conversion but IMO - it's not safe. Just stick with its original specification and you'll live longer