OK now here is a ton of info on latch techniques:
OK here is an article with some diagrams: http://www.llli.org/llleaderweb/lv/lvfebmar04p3.html
and another long article on latch that describes the breast sandwich technique. The whole article may be helpful to you. http://lowmilksupply.org/latching.shtml
and here is a video that explains deep latch that may be helpful. http://www.ameda.com/resources/video
How did laid back positioning go? I am a big believer in this for fixing latch issues. It's more about facilitating baby's natural rooting and latching instincts than really a a latch "technique" but you can use it with other latch techniques or not as you wish. This is a relaxed nursing postion with few "rules" and you can adjust yourself and baby as you wish or need. Here is more on this: www.biologicalnurturing.com & http://www.llli.org/docs/00000000000...astfeeding.pdf
I am really upset you were given a shield in the hospital without follow up care. Not that this is unusual, it unfortunately is very common, and it is really poor breastfeeding support practice. Nipple shields are a temporary fix for the immediate issue that a baby cannot nurse, but they do not, on their own, solve the underlying problem, and they of course can cause some problems. I am not blaming the LC you saw, often they are working under conditions where basically they can only provide triage so the baby leaves the hospital breastfeeding and the hospital can claim they are thus breastfeeding supportive. It is great you have kept nursing so long with these issues and it sounds like baby is doing great, but it is really unfair to you that you have had to struggle all this time with this on your own.
Anyway, you can keep working on this on your own but if there is ANY way you can see a lactation consultant in private practice with experience with helping a baby this age latch and suckle, or helping baby wean off the shield, etc. I would suggest that. Call whoever you find and make sure they are experienced in this area and that they sound like someone you can feel confident in and supported by. Again, the issue may be the baby is simply used to the shield and can nurse without, it but what if the is more to it? In either case, COMPETENT hands on help could be good. You can certainly look into getting help from your local LLL Leaders as well but a LLL Leader is not an IBCLC-however, some have lots of experience-you never know. I suggest you ask around to see what/who may be a good “in person” helper for you.