Wheel specs for lowered 69 stepper????

[JConley]

I have a 1969 Stepside that has drop spindles on it. I assume that it is a 2.5" drop spindle but I don't know for sure. The spindles have Russell stamped on them. The back is lowered to match but I'm not sure how much.

I want to lower it down to a 5/7 drop but the current wheels are the wrong offset. They seem a bit wide and would likely cause a fender rub when I get down to the 5/7 stance. To get to the 5/7 drop from where I am, I plan on utilizing the drop spindles in conjunction with a 2" drop spring in the front. If it isn't low enough then I would cut the coil more to get some wheel tuck. In the rear, I plan on using a 6" drop spring with a 1" block.

Now back to the wheels. I currently have 255/70/15 tires and plan on re-using them for now. I want to get to a 235 size tire after these wear out. What width and offset do you recommend for a 15 wheel to fit these 255 tires now and also fit the 235 tires later? I plan on using some cheap steel wheels for now. I really like the Crager Soft 8 wheels. How do I check my rear end to see if it is the narrow or wide axle? It is a 12-bolt and I assume it's the stock rear end. Again, its a 1969 stepside. Please help me get my wheels right so I can get it lowered more. Here is a pic my truck.