Are you worries about carrying the stones separately? I have GoGameGuru's folding board, which is also Japanese (smaller) sized:

https://shop.gogameguru.com/intrepid-go-game-set/

Lines are straight, board sounds excellent. ProTip: Rubber "feet" on the bottom help the sound & protect the hinge from scratching the surface:

http://www.amazon.com/Shepherd-Hardware-9967-Surface-Adhesive/dp/B007ZUENG0/ref=sr_1_2?s=hi&ie=UTF8&qid=1451527185&sr=1-2&keywords=rubber+feet