Learn me: First motorcycle build

I'm jonesin for my first motorcycle, and after much research and consideration I know exactly what I want: Honda CB350 twin. Something like this:

I love the flat tracker style and that is what I will be goin for. My plan is to start from a frame and build it up from nothing, build the engine for power, and only have the bare necessities. 

So my inquiry to yall is first; anything to consider at all, ways to do things, what and where to buy, cb350 specifics, anything is appreciated. 

Second; This may sound lazy but, for anyone who has experience building these engines or similar, what parts should I get for the best reasonable power gains? Not going for anything crazy, will be doing a rebuild and while Im in there I figured might as well add some goodies

It should be mentioned that this is in no way my first build, just my first motorcycle because I'm tired of spending 12k on every engine swap I think of.

Cool project, should be fun.

Old Bike Barn  seems to be a good supplier for Vintage Honda parts. They have parts for trackers like you want to build. There are other sources as well, CBs are quite popular bikes.

350 is a better engine than 360. Didnt have the oiling issues the 360 has.

350 4 cylinder is a better platform than the twin, revs higher and makes a little more power. Both the twin and the four are raced on a regular basis by lots of vintage racers, so should be plenty of aftermarket go-fast parts. 

I was happiest with the outcome of the Mikuni roundslide carb swap on my wife's 360, that really woke the engine up.

In the example you posted, I think the only things custom are the seat and the exhaust pipe, so it would be easy enough to replicate.  One source for seats, tanks and accessories is Omar's:  https://www.omarsfiberglass.com/