I wouldn't use MG, personally, I avoid all peat. The coarse mix sounds a lot better. But any soil in a pot without a hole in the true bottom can't fully drain. The hole in the bottom of those hanging basket pots is 1/2-3/4" above the actual bottom. When I get plants in those, I discard the thing in the bottom and put holes in the actual bottom of the pot, on the outside edge and the inside edge around the indented hole. If you decide to do some trimming and want more plants, just stick the removed parts in a pot and they should grow. All of mine have survived.

According to this Harris Seeds link, Dragon Wing Begonias are a type of angel wing: http://www.harrisseeds.com/storefront/p-992-begonia-dragon-wing-red-pltd.aspx Dragon Wing begonias are sterile. According to the link below, hand pollination is required Plants are easy to propagate from cuttings. The plants are available at my local Lowes and Home Depot. Check your local big box stores or favorite nursery for a plant. All you need is one from which you can propagate many. Here is a link that might be useful: Dragon Wing Begonias

B. 'Dragon Wings' is a tender perennial. You must bring it inside for winter to keep it. You can plant it in the ground during warm weather though. It is easy to propagate from stem cuttings if you want to increase the number of plants. For winter care, keep it warm, provide light either by a window or under fluorescent lights, and water when it needs it (i.e. don't keep it constantly wet). They have become so available and cheap that you can treat them as annuals if you prefer. A six pack is often less than a dollar a plant.

If you save begonia seed, put them in a refrigerator completely dried out and stored in an envelope (something to keep the moisture out). Some growers say they've planted seed as old as 3 years (and older) and have pretty good germination. Some seed will go bad after a few weeks though. Fresh seed sown right away seems to be the best bet but it all depends on the plant's genes. Some begonias may be in colder areas and drop seed in fall so the seed needs a chill period to be ready to germinate in spring when it warms up. Most begonias are from the tropics though and some may delay germination waiting for a wet season. The seed companies selling DW seeds have pollinated the two parents to get viable seed. I think I explained this earlier with the analogy of a horse and a donkey breeding which yields a mule - the mule is sterile. Same thing for some plants (something about chromosome count, etc.). That is why I think you may have some other begonia than DW. Some of the earlier crosses using U014 came off with names like Candy Cane and some other lesser names that didn't become mainstream (The ABS has some stories about using U014 but it may take a lot of searching to find the data). It took the big seed companies to pour advertising and money into coming up with DW. A sterile beautiful blooming begonia that can take full sun but produces no seed - win-win for most everybody. Here is a reference to DW in the international database of begonias (not complete but one reference) http://ibegonias.filemakerstudio.com.au/browserecord.php?-action=browse&-recid=1501&-recnum=1