Obscure was a good choice for that range before all the forum difficulties changed. Not sure now. A variety of forums will maximise your flezz return, and of course give you a taste of how difficult the different forums are. Check the wiki ‘List of Forums’ page to determine which gives the best cred return for where you are, whilst being as easy as possible so you can avoid spending too much on consumables. Check thread counts, and exit the forum if it’s too low for the forum to be effective for grinding. If you can handle a forum that’s a level or two above yours without too great a cost, go for it.