KTB 60# vs SMG hwarang 70#

Crazybamboo,
If the Kaya is 60# at 31" then it is less than 50 # @28".  If you could draw each bow back to 28 inches  the Hwarang would be much much faster than the Kaya because it will have more than 20 lbs additional force to impart to the arrow. Even if the two bows had the same draw weight the Hwarang is likely to be a bit faster because it is a better made bow. That being said if you are an adult male of average size and strength who is new to archery it is unlikely you could pull that 70# Hwarang comfortably to 28 inches.  The Kaya should be more than fast enough for anything you want to do especially if your goal is to perfect your form which will lead to both speed and accuracy. In fact if you are new to this type of archery most experienced archers would recommend you start with a 35# to 40 # @28 ".

I wouldn't say the SMG stacks earlier.  It's just that it's rated at 70# at around 29".

OK, the guy sold that 70# SMG which he had for sale. And I think it's not worth to order a new one from Korea as long as I have local dealers who sell Kaya bows.
Therefore, I'll stick to the 60# KTB. Now, should I pay extra money to get the long 52" version? Are there big or any differences between it and the standard 48" bow, regarding smoothness, accuracy, and overall performance?
Thank you!

Actually, "Hwarang" is my brand name for the Korean bows I sell.  Mainly, I sell bows now from YMG, but I have sold SMG in the past.  Both makes of bows are very similar in looks, feel and performance, although the YMG uses real birch bark backing, while SMG uses synthetic.  As I popularized this type of bow internationally, beginning back in 1997, my brand name became synonymous with them (much like people say "Kleenex" for tissues).