Your tentative ideal Opening Day lineup against RH pitchers currently includes:
| Travis Snider |  138 (45.70%) |
| Eric Thames | 52 (17.22%) |
| Both | 104 (34.44%) |
| Neither | 8 (2.65%) |
snider will get the job and should, IMO, barring unforeseen circumstances.
Cheap Shot greenfrog.
For all his problems, Travis Snider is a better player than Gabe Gross could be. I listened to the Games on my iPhone, MLB App, and Snider hitting approach has changed - it's what he was sent there to learn. Go here: http://blog.rogersbroadcasting.com/mikewilner/ and you can find Snider interview(s). Gabe Gross was intimidated by his first trip to the Majors, that was not one of Snider's problems. Snider's problems were: consistency and staying healthy.
We saw it last year, too. Rajai Davis hit four home runs in spring training, and then hit only one in the regular season. There was a lot of talk last spring about how Davis' approach had changed, and it turned out to be merely that -- talk.
Snider's spring is encouraging, but the numbers are meaningless at this point.
However I don't know how hitters prepare.
Pitchers however work on various things & in stages. I was very impressed by Jack Morris's method of ST preparation. If he thought it would rain in the afternoon he would trade his start for an AM minor league game start. Also he would just throw a specific pitch to perfect it, so everyone know what was coming. He got hammered a lot. M McDade had a V good ML ST in 2009, of course he hit against fringe pitchers late in the game.
I almost think that every spot on the 25 man roster was basically decided before ST and something spectacular + or- has to happen to change this. But I am not sure.
As far as the value of spring training stats, I've seen all the home st games and one road one. There's lots of reasons that March and September numbers are considered of less importance, and once you see players teeing off against some of the pitchers on st teams you know why. Even regular pitchers are tailoring their repertoire to prepare rather than perform. I can't imagine that the number of home runs Eric or Travis hit against spring training pitching will be considered heavily, if at all, in determining who opens the season in Toronto.
The choice between Snider and Thames is much closer than you think, and will come down to:
did you learn what we asked you to learn? Snider was to develop a new hitting regimen (in the minors, plus consistency), while Thames was to learn better defense.
How well each player does will determine the final decision.