With brushes, it can be a lot of fiddling and I often just use the .png for ease. But there ares shortcut keys in PSE and CS to enlarge/decrease the size and also to adjust the opacity. The shortcut keys are the same. After the shortcut key you drag left or right for size and for opacity you drag up and down. Is that not easy? Oh yeah!
Click HERE to find the original tutorials and get the exact shortcut keys for your version of either software and operating system. Ans if you want some free goodies including a great brush set, try this week's Creative Market's freebies. But each week's items are only good for that week what you see today will be gone by next week. But there will be a new set so keep checking!