I'm sure Percy wouldn't mind if you came down to the lab to observe. Granted, the first few hours just tend to be excessive brainstorming, sketching, and creating diagrams, but since it is a project for you, your input would likely be invaluable.
And I've honestly quite the list. A Robe of Useful Items which basically allows you to store and summon things within magically imbued patches, a Bag of Holding that allows you to carry far more weight than you could realistically, a Chime of Opening that allows you to open any locked door you encounter as long as it isn't spelled shut. I can create a number of potions I might need with a little time and effort. And of course, there's Doty. He's my pride and joy, and I miss him a great deal here. He's a mechanical automaton who acts as my man-servant.
And that shouldn't be any problem at all. Doty was specifically designed and programmed to be able to write. So the manipulation required won't be an issue in the design. Nor will strength.