Congratulations! You're going to be having a lot of fun.
Re #1: % solutions are easy to make if you start from the beginning in your thinking. 1% = 1/100. 2% = 2/100. 0.2% = 0.2/100. For water, g = ml. The only 'problem' that comes up is that it is very hard to accurately weigh 0.2 grams with the scales that most of us own. So, use 2 grams sodium thiosulphate in 1000 ml water, (you're just moving both decimal points one to the right) or 1 gram in 500 ml, if you really trust your scale, but dry hypo is so cheap that it doesn't seem worth it. Also, in my experience, at this big a volume to small dilution, it's not necessary to worry that the total final solution should be exactly 1 liter -- just be consistent.
re #2: you don't need thymol if you keep the emulsion refrigerated until coating and if you use it within a couple of weeks of making.
re #3: just about any developer in the general D76 'family' will work fine.
Best of luck and fun!