Here's the deal.. you may not realize it but at the end of the day your core is a server. The intention should be for this device to just sit there 24/7/365 with no direct interaction unless necessary (ex. making a repair). Two of the top ten absolute worst mistakes you can make while building a server is to under spec the system and go cheap on hardware. 16 GB is ridiculously low and I wouldn't recommend that even for a hybrid with no md's and external storage. Eventually you're going to eat up that space then you have to worry about imaging your system onto a new drive. Just do it right the first time. You may need to turn on extensive logging at some point to pin point an issue, are you going to have the space? Besides, thumb drives are extremely limited on writes. How long will it be until you have to replace that thumb drive? I personally wouldn't go any less than 60GB with external media storage.
I understand not everyone is made of money, and I am by no means made of money, but you get what you pay for. Statistically, you have a lower chance of failure using ssd vs a conventional HD. IMO since you're most likely not using server grade hard drives, you're core or hybrid is not in a temp and humidity controlled room, you don't have systems in place to control dust and other environmental influences, and your core will be powered off and on due to power failures and maintenance, a ssd will definitely out last a conventional HD. If you're intentions are to one day have a core that you're not rebuilding every other month, it would be a good idea to invest in the SSD or a decent raid setup (preferably hardware raid).
To the OP, I've already said this in another post but I don't mind saying it again. I saw an increase in performance when I switched to a SSD. My boot times and regen times dropped after I switched. I use SSD in all my home servers but one and I will replace them all with a hardware raid if I had the cash. IMO it's totally worth it, especially since you can get a SSD now for around $100. Look at it this way, even if it's not much faster with LMCE it should be much more reliable than a conventional drive. IMO that alone makes it worth it.