How to prepare for an opponent?

Indeed. Lots of great advice and encouragement for you, what else could I possibly add? I'm assuming you are well trained in tactical themes and although not stated implicitly, have an adequate grasp of basic endgame theory. Possibly, you're not up soo much on positional strategy. I'm just guessing since you're kind of into Silman's book (talking about imbalances which is another way of evaluating positions in situational positional terms). As it is, studying an opponents repertoire is conducive to "getting positions that you like". I know what you mean. Heh, but then again as some have said, you needn't worry about it as time is flying by and you can't possibly learn or re-learn a new tournament strategy of preparing. Just stay loose. Do the things you can control: buttoning up on YOUR opening prep, keep up your daily chess regimen, don't overthink everything in prep (some things are beyond your control imo) and trust that you did everything you needed to do to get ready; that includes staying connected to Life! Best wishes😉

If it is possible to get hold of games played by players in your section, then I would study their wins and losses, see what they are good at and what they miss on. If it is not possible to study games of theirs, then study old games from that tournament and other tournaments of that type, to get a feeling for how they play at that level. The level you play on doesn't matter, just that you catalog typical mistakes made on that level. Your goal is to try to create those positions for your opponent and be looking for when he makes typical errors. Each level has weaknesses and strengths. Hope that helps.