Hi SallyS,
All of your choices will really be about personal preferences but I can make a few comments.
With thinner toppers … you will feel more of the properties of the latex underneath and less of the properties of the topper and with thicker toppers you will feel more of the properties of the topper and less of the latex underneath.
The Lanoodles is about 1.5" thick but the thickness isn’t even like a solid latex layer because the lanoodles are spread out. As you know it has “pieces” of latex in it so it would be less resilient than a solid latex layer but it’s quite thin so you will feel more of the latex underneath it. You can see some of my comments about it here and here and it’s somewhat “in between” the feel of a featherbed and a solid latex layer. It’s more about adding some “cush” and a little additional pressure relief. The lanoodles don’t really move around that much when you sleep on them and they can be smoothed out using your hands (not fluffing it up like a featherbed which would shift the lanoodles). If you pick it up and carry it instead of rolling it up when you move it then the lanoodles will shift and bunch up and then they are difficult to even back out again. It would be more difficult to even them out if they were inside a mattress cover than if it was being used as a topper outside the cover. It doesn’t feel at all lumpy or bunchy to me … just soft.
I think it may be well worthwhile trying the PLB toppers because they are the softest latex toppers you will find (mid teens ILD) and would make a good reference point for really soft latex.
If you do go to Seattle Mattress I would also make a point of visiting Bedrooms and More as well because they are close to each other and they have a range of toppers you could try. Seattle Mattress has 19 ILD Talalay toppers in 2" and 3"
A thicker wool topper will most likely be more prone to impressions than a thinner one because there is more wool to compress although it will also tend to even out over time if you spend some time sleeping on the parts that you would normally sleep less on and they “catch up” to the parts you spend more time on.
You are very light and quite sensitive which means that softer toppers would likely be important so my “best advice” would be to spend the time actually testing the options you can before deciding.
Phoenix