you'll find very few people here actually do their own fourth order designs. Those that do spend a ton of time on them and are busy doing them for others as well. Im not a fan of the fourth order. mainly because I dont have the time to design one or build one and because I dont feel its the magic answer to being loud. I see way more failed fourth orders that either play super low but not super loud or just dont get loud than I see 4th orders that are wowing.
You'll notice that alot of loud 4ths i mean really loud are all designed by the same guys. You'll also find alot of guys who say they love their 4th order but wouldnt know loud if it was sleepign with their girl.
my advice to you is either pay singer or someone who has a proven track record for designing loud 4th orders or be ready to do a couple different boxes when you are unhappy iwth the first.