Hi flightcontrol,
Comfort is very subjective and different people can have very different opinions about the type and firmness level of latex that would be similar to a particular memory foam topper.
There is also more information about how latex and memory foam compare (and don’t) in post #2 here but they are very different types of materials with a very different “feel” and they are difficult to make an “apples to apples” comparison. If you aren’t familiar with how latex feels in general then it’s also a good idea to test some latex locally to make sure you like it because just like any type of material some people will prefer it over any other type of topper and for others they may not like it at all.
Once you have confirmed that you like the more resilient feel of latex … then post #2 here and the topper guidelines it links to has more information that can help you choose the type, thickness, and firmness for a topper that would have the best chance of success and includes a link to the better online topper sources I’m aware of as well.
If a 2" topper has worked well for you I would tend to stick with a similar thickness (thinner toppers can have less risk of alignment issues than thicker toppers) in a firmness level that was probably a little softer than what you are considering (19 - 24 ILD would be more “in the range” of the ILD that more people would do well with “on average”).
The return/exchange options of the supplier you deal with may also be an important part of your choice so that if you choose a firmness level that is firmer or softer than you prefer you would have the option to change it for a different firmness level.
Phoenix