What are my options with FD tank

Interesting mij, I looked at the web site you mention, and all I can find is the SCBA adaptor assembly for $159, which is over $100 more than the eBay one. Could you please post the link for the one you are talking about? Below is the link for what I found on the web site you recommended. I haven't had any problems with too rapid a fill, just keep your attention on the pressure gages and you'll be fine. Thanks!
http://experthpa.com/cart/cart.php?m=product_detail&p=66