Hello LostMyReligion,
Welcome to the board! It's good to see you had the courage and honesty to overcome your fears and begin to post. There are a lot of fine, caring people who can help you in many ways. I hope your ex-JW support group is helpful, too.
I'm glad to see you're taking things slowly with your JW son. You didn't mention a Mr. Lost, so it would appear that he's not a consideration for whatever reason. Don't ever feel guilty about finding the truth about "The Truth". It takes time to get used to the idea that JWs don't comprise "God's organization" and it can take a long time to get over the guilt that has been ingrained in you for 30 years. But it will pass, especially as you associate with people who left the Borg behind and live normal lives.
Given what you posted, it seems that the gentle approach will be best to show your son about your newfound knowledge. Some people can take being hit over the head to make them wake up; others can't. You know your family best so you have to do what you think is best. It might take years, or he might never see the light, or something might strike him like a bolt out of the blue. You have to be mentally and emotionally prepared for any eventuality. You might also open up to your younger son and get him involved. Often, brothers or sisters can be a lot more effective than parents in getting someone to listen. However, watch out that the younger one doesn't get scared right back into the JWs. That has happened more than once.
One technique of drifting away and simultaneously creating a 'problem' that your JW son will probably want to 'solve' is to gradually cut down on meeting attendance and other activities. If people ask what's wrong, usually just mumbling about being tired or busy or whatever good excuse you can find will put them off long enough for you to drop to the edge of their consciousness. If people push you, don't give in to the urge to spill it all, because likely as not the person you tell will get very scared and run straight to the elders with charges of apostasy against you. Then you may well have lost the battle for your son.
The watchword is subtlety. Dropping little problems here and there, which are not solvable within the Watchtower system except by ignoring them, will often spark the interest of an intelligent JW. No pushing, just bits of information set out as something of interest. You'd be surprised how internally upset this can make some JWs, but not at you since you only pointed out something that they verified for themselves. In my experience these things have little to do with the core of JW religious beliefs, since trying to tackle them is like trying to get through 15-inch steel armor. There are much more effective topics that will get a JW to think, without tripping his 'apostasy' alarm.
One other potential problem for you personally is what you're going to do with your religious life during your winding down process. A lot of people will try to pull you this way and that. The best course is to sit tight for a long, long time before making any definite decisions. During the interim, read, read, read! Take a college course or get a degree. Talk to people of all sorts of persuasions and don't let yourself become too convinced by what anyone says. Learn how to think for yourself all over again, and get rid of 30 years of JW training that teaches you to just accept what an apparent authority tells you. Learn lots of things you never had time for or interest in as a JW, then discuss it with intelligent others. Even get involved in arguments and debates. All of this will help you figure out for yourself what you want to believe or reject.
Whatever you do, you'll find plenty of support on this board.
Oh, and don't let the braindead JW defenders here bother you. I'm sure you've already spotted them, as they're far more braindead than your average Witness cult member.
AlanF