I don't know if you realize it but tech manuals' purpose it to increase your experiance in a given discpiline proportionally to your Int and number of tech manuals in your inv. Since you might need even a large number (might be around 10 or more) of tech manuals to assemble some of the best items you should find a place to store them. It's not convenient but you're not encumbered at least. If you need only one manual however (like I do when I want to make bullets) just give it to some strong party memeber when you don't use it. Sorry but you can't "learn experience" from these manuals - unfortunately.
So inotherwords they give you a temperary increase in that area while you have them in your inventory?
You can store them in a convenient chest, like one in a hotel room or warehouse, where you stockpile the components until you have enough to make a worthwhile batch of items. Also, using an intelligence spell or potion at the same time can save you a manual or two.
