I don’t understand what you mean by wash the points through Singapore? If you use the card in Singapore, yes, you will earn double points, so 2 points per dollar. But it’s not restricted to Singapore, but any overseas transaction will earn you double points.
Do you mean transfer to Krisflyer first and then to Velocity? In that case, sorry to disappoint you, you will lose points by doing so. The 1.35:1 exchange ratio works both ways. So it’s the same 1.35KF points to 1 velocity point. The information on Velocity’s website is misleading, so not only you, even some experienced blogger in US got mixed up. It is much clearly stated on KF’s website. So if you want VA, then transfer directly to VA.
Bear in mind, recently Citi had devalue the transfer rate from Citireward to KF and VA without notice. Although it was reverted back due to the dissatisfaction from many customers, they have since change the T&Cs and have admitted the possibility of devaluation at anytime. So Signature earn rate will drop to 0.75 KF/VA per $ very soon. Many of us are expecting by the end of the year. So if you are considering getting this card, just bear this in mind.