Hi there, both boards are great, the LW is actually pretty quick for a board of it´s size, certainly handles the sails over 9sqm and super light winds better than the 140, which is a full on race board - the LW will plane considerably earlier and more in the passive planing mode, whilst the 140 with the bigger cutouts and narrower width, will need more wind to get going. You are close to 100kg, intermediate level, light winds - clear choice is the LW for sure!
Yes, the 140 is faster and with it´s narrower outline it will gybe tighter. On the other hand the LW planes far earlier, has a very good top speed, comes with a fin and at a lower price - pretty much aimed at customers like yourself actually! 😀