Surbie, if you're short of space, start stashing things under beds, perhaps on sheets of cardboard so you can pull them out easily. That space is mostly dust collectors for most people and usually doesn't get warm. Any dust-laden socks can get kicked out
Also, keep a running list tacked somewhere of what's under the bed so you know what you have and where it is. I know of people who store spare water in 55 gallon barrels under their beds as bed supports. The mattresses are a tad high, for sure, but water shortages aren't a problem for them.
Rachael, too thick jams/jellies can be due to either too much pectin or too long a boiling time where the jam reaches more of a soft candy temperature. For beginners, I feel uniform jar sizes are easier until you're more proficient with the process and can judge times, etc for mis-sized jars. Many of us have been at it for decades and can easily adjust whatever is needed.