I'm having trouble deciding to go all in on this guy or not, it is a week before the all-star break.  I have 20 in int scouting.  He is 19 years old which I think means he likely won't hit his projections? Ratings are

dur-27(29)
health-81(90)
stamina 63(90)
control 48(63)  This is why I'm having trouble evaluating.
vsL 64(85)
vsR 68(97)
vel 31(32)
gb 54(64)
pitches  71 71 35 40 21  (78 82 46 53 26)

Someone is going to spend a ton of money on him, likely after a bidding war, and I think that's going to cause him to be very overpaid for someone with that mediocre control.

Personally, I also look at control, velocity and gb/fb together, and I like at least 2 of those 3 ratings to hit at least 70. And that's not going to be the case with this guy.

His splits will be good, to the point where I'd bid on him. But once the bidding gets above $10 - $12 million, I'd bow out.

Don't pay the big bucks for him. If you can get lucky and get him for a reasonable price, he should be an SP3/SP4. I don't like the low control and mediocre pitches for a high priced IFA.

I don't think you're having trouble evaluating. You've made your evaluation, and even though his R/L splits are great, his control isn't where you want it to be.
Sounds more like you're debating whether or not you'll miss out entirely on a quality guy as it gets later in the season. I've been there, and that's always a tough spot.

For me, a lot depends on how my prospect budget, or potential prospect budget, compares to the rest of the league. After checking your world, it looks like you are #2 in available payroll and with it being over halfway in the IFA season, it is a tough call. With four teams left in the league with over 20M available to spend on an IFA, I doubt he goes for under 20M.
I think the guy is worth the money. Here is a similar guy:
 Hardball Dynasty – Fantasy Baseball Sim Games - Player Profile: Alfredo Torrealba
His splits won't be quite as high, but his control will not be as low either.
I'm not sure why you think being 19 means he won't develop. With your 20M scouting, I wouldn't be surprised if he gets within a few points of each of the projections.

I just thought usually 18 year old internationals would hit projections where as 19 year olds wouldn't quite get there.  I would expect him to get close.

Don't assume that. A player has about 90% of development in the first 4 years, and offensive players will max out by about 26 years of age. Pitchers, maybe another year or two. So any player from 18 to 22 has a good chance of 4 years of good development. If you have 20 in IFA scouting, and you get him good coaching, expect him to come close to projections, barring major injuries.

Even with a $20m scouting budget, projections are still slightly fuzzy.

For that reason alone, you should never assume that somebody will "hit" any projections you see.

Just an observation- 22 year old position player IFAs just don't develop. With them, you get what you get, nothing more.

This guy didn't develop much in his 3rd season and he played a ton and  I had pretty good coaching I believe. He stopped after 3 seasons, and barely developed his VL at all. 

 Hardball Dynasty – Fantasy Baseball Sim Games - Player Profile: Vladimir Mendoza

19 yo internationals develop much less than 18 yo internationals, and less than 19 yo college players.  But it's not that they won't hit projections, just that they won't develop as much.

For this guy, I'd expect him to get to something like control 63, VsL 80, VsR 86 (that's a very crude guess).  Assuming his first two pitches end up roughly as projected, that's a mid-rotation starter.  Proceed accordingly... a week before the ASB I might break the bank.