Hi debmot,
[quote]1) 3" vs 2"? (body weight of sleeper less than 150#, was comfortable on 3" talalay ILD # 14)
2) Is it worth $49 extra for a cover when it will be under a mattress pad and can be moved, stored in a cheap mattress bag?
3) Re ILD #'s, if #14 was comfortable, is #19 the best choice? will the others be significantly different?[/quote]
There is no way to know for certain until he tries it so my “best” suggestions would be to either use a similar topper to what he is used to if it works well for him (3" of 14 ILD Talalay) or to use the topper guidelines in post #8 here if you think that a different thickness or firmness level may work better for him.
I would add the cover because it can help prevent the latex from oxidizing and breaking down more rapidly over the longer term. Post #3 here can give you some idea of the effects of using different types of coverings around latex.
If 3" of 14 works well then I’m not sure why you are considering changing it. 3" of 19 ILD would be “one step” firmer and while it is also in a soft range for most people it would be noticeably firmer. It would still be “in the range” that would work well “on average” for most people of your son’s weight but the feel and performance of a topper also depends on what is underneath it so his own experience will really be the only way to know for certain.
Phoenix