You're WAY better than i am, but if no one will respond, I'll add my two cents. Definitely spend it all at some point. It maximizes the number of recruits you can find. Depending on if you're in D1 2 or 3, some people save some of that budget for RS2 in case your first few targets get a lot of attention from better coaches (especially at D2 and D3) and you're left scrambling. Your method of not spending it all doesn't necessarily hurt you. But if you're not spending, say, $5,000 of it, well you're missing out on X amount of recruits, some of those recruits being better than the guys that you've scouted/signed possibly.
Private camp is great (2 scouting levels). Assistant search is great (able to target certain positions). I use that same method. But i use FSS for neighboring states as my first step. I think it's an inexpensive step that can save you a few dollars on the last step your mentioned, of individually scouting a recruit to get them to level 4. Wow, my first intelligent post.