you can just put in the 20 grams (or 40) and keep the beans in those one way valve bags you buy them in (from better coffee bean suppliers)
give the hopper a wash once a week (if you use it)
i dont have a hopper on my Rossi RR45 i put the 40-50grams of beans into the top and put a sink plug in the top to stop the bean jumping out.
if your going to do decafe then normal i would look at getting a doserless grinder and just either grind into the Ghandle or a container.
doserless are generally easy to give a quick clean with a brush and a wipe. if you did the decafe 1st then yours, then clean. when you grind a again for decafe grind a tiny bit more and dump the 1st few grams
depending on what your planing to upgrade to you might be better to stretch a bit further with the $$$ and go one step better in the grinder and it might last you more upgrades etc.