Ask for a better price on the K6 Wee. State to the Wee seller that you can get an L2 Vee for around his asking price of his K6 Wee, so you are looking for a better price.
As an owner of a K6 Wee myself, there are times when a strong headwind makes me wish for more power. Then 99.9% of the time I do not need that extra power or the possible problems that the Vee is reported to have, aka stator magnets coming loose, stator failure, clutch chudder, lean fuel mixture, lack of low speed throttle control, etc to name but a few.
As in the case of my friend's Vee, once sorted the Vee is one hell of a bike. Maybe I'm totally wrong about my views on the Vee and you may get a trouble free bike, if you do decide to go that route. Good luck with your purchase.