Just as an aside, you may want to consider a gravity feed as opposed to a bottom/siphon feed.
I have both a gravity and bottom feed and I find that the gravity feed has become my more utalitarian brush. I use the bottom feed for spraying large areas (like for coats of future or fuselage colors), but I use the gravity feed for everything else. The gravity feed can handle large areas, but it means having to refill the cup every now and then.
The gravity feed wastes less paint as there's never that little at the bottom that you can't reach. You use less air as the air is used to push the paint out instead of creating and maintaining a vaccuum. And for the same reason, you can make finer lines. BUT, changing colors means that you have to clean the cup after each color, which can be a bit time consuming.
The bottom feed is nice in that you can paint large areas without having to worry about running out. The bottle can also act as a storage container, which is nice if you have just whipped up a custom color. Swapping colors is easier because you just pull off the bottle, run some cleaner through the brush and swap on a new bottle. BUT, there will always be that little bit of paint left at the bottom of the bottle that the straw just cant't pick up. And because you need a minimum PSI to create and maintain the siphon vaccuum, you are limited with how fine of a line you can spray.
FWIW, I have an Iwata Eclipse BCS and an Iwata Revolution BR.
-Fred