yeah you need to use a bit more than 7 grams, especially if its low quality. try 7 grams of nice bud!!
you need to put your glass dish, on top of a larger dish of very hot water for a few minutes, after blasting. MAKE SURE THIS IS DONE OUTSIDE. that will get rid of that white cloudy stuff. its normal, and not necessarily safe to smoke.
soonest you can sneak a little test hoot is after 15 or 20 mins of hot water purging. OR sometimes I turn the oven element on low, and hover the dish a few inches above and give it a nice heat purge.
of course you can smoke it on the blade. you just need 1 hot knife though, a brand new knife absolutely sucks. a heavily used one is the best. just for reference.. heat it red hot, then let cool for about 10 seconds, then hit it... thats about how hot you want it, it doesnt have to be red hot. youll get it with practice. too hot makes it VERY harsh. also, be sure to keep the knife perfectly straight and level, or there will be sticky oil droplets on the carpet/floor
You will definitely get better everytime. Reminds me of myself well done man. Pretty decent for first shot. But I'd reccomend getting a nice concentrate peice. I'd definitely reccomend checkin' out Silika pieces. You can either get a concentrate spoon (with nail) for around 50 or you can get a rig for more. I got this rig with some other things for around 100-120 bucks at my local head shop, can't seem to remember.