Hello sersam,
the weight limits are equal at the LT, 5.xx or SX, you’ve probably noticed that.
Surely Ming cycle has calculated a safety tolerance, I mean the LT should work fine.
However, please tighten the seat molding bolts correctly to avoid slipping of the molding (and damage of the seat pin). 
Refer to page 8 and 9 Strida manual revised.pdf