Hi Mark......I have been building steady for almost 4 years but,I built as a kid from about 9 to 14 years of age........I gather reference photos off the internet "Google" and reference photos here on MCM from other builders.......I just eyeball and measure dimensions on my own.......they are not perfect but,I try to do the best I can.......I am no way a professional.......but,I am happy what I come up with......thank you so much for your kind words.