racking up Hilton points
Hi guys, I'm curious what the best way is to rack up Hilton points with signup bonuses. Is it with the Citi Hilton Honors + the AMEX Hilton card? Each one has a 40,000 point signup bonus...the Citi one with $1000 spend in 4 months (easy), but I can't tell what the AMEX's requirement is though?? The AMEX also appears to get better points, 5 per $ at supermarkets, gas, etc. vs. 3 at Citi.
Also, are each of these churnable for this bonus? If so, how long do I have to wait between signing up for the Citi one, for example, before I can cancel and re-apply?
Any thoughts/recommendations/help would be greatly appreciated!
Thanks again.