Yet again the site froze when I tried to send my post, and yet again it did it when I'd forgotten to copy my words of wisdom first..
I've been trying to find this out too. I suppose the ergonomically correct height for your table is going to depend on YOUR height. I'm using a dining table at the moment and my feeling is that it's too high - but I'm only 5ft 1in: if I were taller it might be OK. I've been wondering about measures such as gap between knees and the underside of the table, or position of table in relation to my torso or elbows. Using your ironing board to find out what works is a brilliant idea, and I must try it!