The center post on the Simplicity is the same fixed, solid, no leak design that we use on the Precise/PrecisePlus line for over three years and we've never had a failure with that design. We don't want to get away from that sort of reliability on the Simplicity, so you will have a small gap as you do on some of the PrecisePlus's depending on what tank/rba you have on there. Some rebuildables do have an adjustable post that allows for adjustment and you can adjust them down. Not to mention, we will be making our own completely integrated feeder/rba for the Simplicity down the road.
Why can't a 510 atty, Joye etc. be the default flush fit? Most all RBA center pins are adjustable, I can't adjust my HH, Joye and Ikes. Just wondering as I scratch my head with my credit card.
Oh ya, I don't have a problem with David sticking to his guns with 510 spec., It just seems like all the the pics I've seen with a 510 atty on the Simplicity, seem like they could be screwed in another mm. I'll buy one no matter what but, I would use it with HH357s' 90% of the time and don't wanna look at the gap. Maybe an optional center pin depth in the future??? 
