How does it go over?

90% of the time I have tried it has not gone well. If you are recruiting and thinking about wanting to RS a Juco then it is important to try and inform of RS, that is the only way I have been able to do it. 

Will you lose him if you do?

telling him you want to redshirt is just negative effort.  he will always say "your crazy" or something along those lines.  But if he is still considering you even with the redshirt offered, you should be fine.

it's usually easier to do when you are not in a battle.  i usually offer a few HVs and a few SVs (since scouting visits are effort that can't be refused) and 10 calls + 10 letters.  that's probably overkill, but it's a mess when you offer it and then he stops considering you.  

so if you have enough $$ and really want the guy, make sure you give enough effort that will counter the negative effort of redshirt.  I have no idea how much negative effort it is, but I would guess something like negative 2 home visits??

I've found that if you inform of redshirt, somewhere between 2-3 home visits is enough to counter the negative recruiting effort.

Put enough effort into a guy to where he is considering you. If you aren't in a battle at all, give him 2-3 home visits or 1-2 campus visits (depending upon your recruiting style) and as dtm1500 said it will effectively counteract the negative recruiting effort of informing him of redshirt.

If you inform him of redshirt and you sign him, he WILL accept the redshirt 100 percent of the time.