You have a few good options that can help you. First and foremost I am not a fitter. I've done many, I'm well read, and I know just enough to be dangerous as I call it. I can point you in the right direction but cross reference with somebody with more experience before you purchase.

With that out of the way here are the options as I see them. Road bike fits are a lot more forgiving than a TT fit so keep that in mind. Also get the current setup on the old road bike mapped out so you know what DOESNT work for you. Get your saddle height, reach and stack. It's easily done with a tape measure. I assume you have got the saddle height correct where you only mentioned reach issues. The next thing I'd do is purchase an App (Bike Fast Fit) and get the details on the angles you have on the current bike. You then should be able to surmise what changes to reach, stack and saddle height will be ideal for you.

Check out these basic guides: GCN Basic Fit , GCN How To Perform Fit

Almost all bike manufacturers publish geometry for their bikes. It may be in the user manual but more often than not it's on the models website.

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"Train so you have no regrets @ the finish line"