At the moment, my hit rate of offering boosts and having them accepted is about 50:50. Maybe a little better, in favor, but not by much. So, bear that in mind.
I also dual box so would have to pay for charges anyway. On that basis I just offer boosts to third parties and generally don’t accept tips (which are rarely offered!). In your case, boosting would also be a way of playing and talking with others, so costs of charges would be trivial by comparison with benefits.
Just remember though that you can also nuance the economics. When others have boosted me, they will sometimes offer to also take my ore. This is usually offered at some discount, 90% of Jita-buy being typical, which can work well for both sides. For me, I was getting faster cash flow by not having to dock, compress and haul. And even though the unit price was discounted, my cash-flow was also increased by the boosted mining rate. As long as you, the orca pilot, can then on-sell this ore at a high enough price to make a profit (ie minus all broker taxes) then you are “leveraging” the fact of having given otherwise free boosts.