Does it make difference? Early in recruiting or wait until just before signing? Thx!

No reason to wait if you know you want the player.  The SIM will continue to accrue consideration credit, and probably more importantly another coach could beat you to the punch.

totally depends. you have to weight the value of staking a claim on that player against the weakened status of your team in recruiting that claim brings. not sure what level you are talking, in d1 that probably is most relevant - in lower divisions, id probably stake my claim more often than not. then again, if its over 360 miles, i dont know. just depends on the specifics. 

It can be worth waiting until at least the 2-5 AM cycle the first night of recruiting, because that way you'll know how much it's going to take (by seeing how strong the WOTS message is). Beyond that, I see no reason not to go early (in D2 and D3)

thats a great point, you definitely want to know if the player is a sim's top target or not. that has a HUGE difference in how expensive the player is. if you cant tell just by looking at them (which is generally tough except in d1), then the WOTS can be incredibly useful information.