Thanks for the info.
So I have the posts and bushings created. It sounds like now I want to use a steel rod to properly align the 2 posts, then locate them on the top tube. How do I verify that they are vertical? They are too short to use a level.
I am not sure how short, you consider to short, but if you have a standard 24" level (digital) and any strait piece you consider good (a 4 foot level) placed on your bars, this will show in 1/10 of a degree, anytime your that close, your close enough.
Always start with this same level test from side to side on your floor tubes on the frame. Have things solid underneath for a base and your good to go. i.e. sitting on loose gravel, will not suffice.
Best of success!