Scaling sucks. Period. There isn't a simple/easy way to do it. Here's the best advise I can provide...
1. Measure what you can. If it's a helmet, pick the height, width or depth that will make estimating your size easiest.
EXAMPLE: the batman helmet has ears sticking up on the top, so don't use height - use the WIDTH and measure about how wide you need it. the adjust the scale in Pepakura to match.
2. Gamify your work, by seeing which part you have to print and test the fewest times prior to hitting the scale perfectly.... this doesn't speed things up, but it might help you stay sane.
3. Only print the bare minimum pieces that you will need to test fit the area you're building.
EXAMPLE: for the batman armored forearms, just print the wrist band area and check that. See if it fits correctly before printing all the rest of the pieces.
4. Don't glue the testing pieces all together if you don't have to. Use staples, tape, etc... you just want to gauge if the scale is correct.
5. Invest in 3M or other paper-producing company, as you'll be inflating their stock with all the copies of these pieces you'll be printing.
6. IF there is a common scale (like there is with the batman armor files from
ATZLAN), record the scale you used successfully for one piece... as that scale will likely be solid for your other pieces.
7. Keep a positive attitude. It's a solid piece of advice for general life, but I'll share this story... One of my favorite build-friends discovered pepakura through an anger-management class. My friend told me that pepping pieces was like Yoga or meditation for him. So, if I get all pissed at a tough scaling problem or difficult file, I try to think about how Zen my pal was while making model after model.
Hope this helps - keep building!
