76' CB750ss - Rear wheel help

Motorcycle noob here, please bare with me

I want a wider rear rim/tire...or as wide as I can get it so that it fits the stock swingarm. I've been looking at Buchanan's Sun Rims for sizes and spokes etc. The current rim is 19, both front and back.

Now judging by the condition of my current rear hub and sprocket, it seems to be in pretty decent condition. Just need to clean it off a little bit.

So i'm thinking a 3.50 x 16 inch rim for the rear (or would a 4.25 x 16 fit?), and a 2.15 x 16 rim for the front. The spokes on Buchanan's website say, for the rear drum or disk:

KHON202SS HONDA CB750 REAR DRUM or DISC to (3.0)x16" HD DP D/C RIM - S/S
KHON202SZ HONDA CB750 REAR DRUM or DISC to (3.0)x16" HD DP D/C RIM - S/Z
KHON202C HONDA CB750 REAR DRUM or DISC to (3.0)x16" HD DP D/C RIM - C

So i'm not really sure which spoke kit to order?

Now for tires...I'm confused. I want to get Michelin's road pilot 3 tires but i'm not sure which set to order for the front and rear wheels. since the only size they hare for the rear tire is 17 inch.

Please help!

more pictures of the rear wheel:

cognitomoto has excel rims.

http://cognitomoto.com/collections/hubs-wheelgoods/products/excel-dimpled-aluminum-rims?variant=509428393

im assuming this will fit with my stock rear hub?

Any of the spokes listed will work with your rear hub and a Harley 3.0 x 16" rim. The designation at the end of the numbers is the type of finish. S/S is stainless steel, C is chrome and I think the S/Z is a type of twisted spoke in stainless. Fitting a 16" rim on the front may be a little more tricky. It's kind of hard to find a 16" in 2.15 drilled for a Honda hub, so it becomes a special order and is $$$. A 75-77 Honda Goldwing fork is wide enough to run a 3.0 x 16" rim on the front. Buchanan can also provide the front spokes but they will be special order.

Well the plan was to get a gsxr front end, swap that in. So my focus right now is the rear rim. So I was thinking I could take my rear hub that I have now and purchase a wider rim from Buchanan or http://cognitomoto.com/collections/hubs-wheelgoods/products/excel-dimpled-aluminum-rims?variant=509428393 and lace that up with my current rear hub. Will that work?

I want to make sure I get the right thing before I purchase something. Everyone seems to vaguely point me in a direction but never tells the truth

Be careful about the width of the rear rim and resulting tire. There may be interference with the swingarm. Also, if you use the 17" rim, you may be required to purchase a custom spoke package.
Rider

It should be dead easy to find a CB750 rear wheel with 16" rim there were 'bazillions' of them converted in the 70's (although a disc brake hub may be a lot more difficult to find)
May be worthwhile getting a cheap one though to see if you actually like the look before spending $4~500 on parts

I set up a customer's rear disk wheel like yours with a 2.50x18 Borrani (about $225 shipped). He uses it for vintage road racing and is happy with it.