JMO, I have a hard time believing you can seal a spoked rim. The spokes go through the rim just like a bike spoke, with an adjustment nut. The nut rotates for adjustment AND as you go around corners. Wire wheels are a bad idea. They went out in the 60's due to the lack of performance, wear, and detuning. I had them on a 68 Spitfire and learn to hate them. A friend had them on his E-type. His where beefier and he didn't do corners like I did. He didn't have the same amount of issues: hubs had play fore and aft, spokes creeked on corners. So the wheels were flexing in corners. I had radials and tubes. No one back then mentioned and issue with tubes inside radials.
Honestly, I understand the nostalgic uniqueness of spokes, but. I really don't think you can effectively seal the spokes without welding them and that is metalurgically stupid. You can't epoxy them, it will crack. Maybe a non hardening coating that allows the spokes to move but won't flow with rotation.
Since you aren't concerned with originality, follow the above advice: dump the nostalgia and get new 16 inch rims. Check with some local wrecking yards for a good set of newer MB wheels. Very few after market wheels take the hugh MB center caps.
Tires? 10 year old tires are unsafe, act weird, track weird, grip wierd. I had to dump a set of Pilots that had nearly full treat but broke down inside over the 10 yrs of sitting around. I thought I had alignment troubles. I mentioned I'd never buy michelins again and the tire guy said it was the age not the tire.