Why not just sign up for all the main ones and clearly state your intentions?
This.
You won't chafe anyone's fragile ego if you make it clear right out of the gate, meaning unquestionably clearly stated in your profile blurb that you're Not interested in a hookup but rather just companionship for the night. A dining partner or just a coffee mate. If this is put out right there in your profile, the only guys who will ignore that point are those who go just by pic and never bother to read the profile. But there's still the discussing that might otherwise lead to a place to meet up and get jiggy but this time you just decide to meet up for coffee or dinner and can take the time to once again make it clear this is NOT a hook up for you.
If they bypassed the profile where you made this clear and they're being pretty insistent they are expecting a hookup, they'll probably drop it pretty fast, which you want. Don't waste much time on those who can't be arsed to even read a persn's profile.
On the other hand, those who DO read the profile will already know that this isn't your goal, that you just want to meet for a purely social engagement and are much more likely to fit your needs.
In the end, it's up to you to make your needs clear up front and weed through those who respond until you land on the right dude who is also good with a simple platonic meet-up.
Chances are HIGH that there will still be one or three lazy guys who you'll have to weed out because they will NOT bother to read a profile but the ratio of these should be pretty darn low.
Of the two apps mentioned above, Grindr and Squirt, I'd actually lean more to Squirt. Grindr, in my view, is much more strictly a hook-up app. Squirt seems more casual and relaxed.