I don't think you should waste your time making anything special, these have been around for ages in plenty of different variations.
Here's what I had and have on my connie.
First up is a $.99 cup holder found at any gas station, car wash, walmart, grocery store\pharmacy automotive isle.
Drill two tiny holes, get two zipties, mount to clutch reservoir.
Note I had to remove this once I put the larry buck dash shelf on the bike.
Next, handlebar mounted bicycle bottle cage, about $5 at most bicycle shops or $3 shipped on eBay from china. Has a welded on handlebar clamp that's rubber mounted.
In the center of the above picture is a "topline barhopper" bicycle handlebar mounted CUP holder, I stress cup because it's tapered, perfect for that morning cup of Joe. Cost about $7, or you can buy it through Aerostich for 4 times that price if having an aerostich sticker on it makes you feel better.
Right side is very high tech, first, take a L bracket, drill hole, mount L bracket on the right hand side threaded hole under the cap which once held the mirror for whatever other bike kawasaki had these brake and clutch perches on. The other holes on mos L brackets happen to line up with the holes on mos bottle cages. Then buy any old bicycle bottle cage you please, I chose the Bell expandocage which has a rubber adjustable "belt". So if I want a 64oz gaitorade bottle there I can has my electrolites. Bell bottle cage is a whopping $4 at walmart or $5 shipped on eBay.