Can one practice laining from a Sefer Torah?
Yes , one may practice "laining" from a Sefer Torah. In the past each person would have his own Sefer Torah written so he could learn from it. (See Sefer Hachinuch Mitzvah 613) So, therefore preparing the reading from a Sefer Torah would not differ. The Sefer Torah should not be removed from the Bet Knesset for this purpose and of course proper decorum is strongly advised..