To Potty or not to Potty...

Okay, so here's the deal:
Let me start off by saying that I really don't know that either Jack or Quent are ready for the whole toilet learning thing, they are only 20 months old, but I recently (after much potty chair research) bought them each a small potty.
See below:

Jack checking out his new potty

Quent checking out his new potty

Here's my reasoning for that purchase:
Jack has been able to make himself pee when he wants to while he is naked. He has been able to do this for a little while now and has amazed us and Gramma (who I am not quite sure believed me when I told her he could) with his abilities. He will pee on the floor, stand while in the tub to pee, and get you wet during a diaper change. Each time he will preface his urination with absolute stillness, laugh and a grin and say "pee pee!" He delights in his ability no matter how a small an amount he can conjure up.
So, given this amazing fascination, I did not want to waste his interest by not giving him the opportunity to try it on the potty. And I was super scared that he would lose that interest and I would have missed my "window of opportunity" (just a little shout out to my ACTS buddies who might be reading)
Quentin, on the other hand couldn't really care less. He thinks the potty is cool and all, it makes a great hat and his friends Handy Manny and Cookie Monster love to sit on it, but he has not yet made that same connection Jack has.
Both boys will sit on the potty with their clothes on, and before bath I will see if they want to sit on the potty with no diaper on. Twice now Jack has actually peed on the potty seat!

Now the dilemma:
Do I just jump into this toilet learning thing and go for it? At least with Jack? My gut tells me he is too little to really get it yet, is he? I know I used to talk to parents about this subject all the time when I was working but sometimes your job knowledge just doesn't apply to YOUR kids. I know that I do not want to push him too soon (him meaning Jack, I KNOW Quent is not ready yet) , but am I doing him a disservice by not encouraging something he obviously is interested in. I would tell someone else to 'let your child lead', and that is what I want to do too, but when do you decide to assist and encourage rather than just follow their lead?
I guess I have a lot more research and thinking to do, huh?
So, ideas? Suggestions?
I'll keep you posted...