Hi! As long as you maintain the volume, & don't go to too 'wild' extremes in altering the box-dimensions, you should be on the safe side. But be carefull when/if you alter the dimensions! Remember, it's better to measure/calculate twice than to have to use the saw twice... If you're a beginner, I think these boxes are almost as simple as it gets - so in that sense, it's a good place to start.I'll bet Wayne will send you the plans when he sees your post!