You’re going to hurt your success chances by using your own mare versus a recipient herd. It’s really difficult to time both mares exactly, and the success rates on a transfer are already not a sure thing.
The challenge you might run into at this time of the year is availability of recip mares/cost - they may already all be spoken for, and those that aren’t may demand a higher price tag. Generally, it’s safe to budget about $10,000 for an embryo transfer (excluding stud fee, including receip mare from a herd).
My biggest piece of advice is to also budget for foaling out at a dedicated facility. 95% of the time, everything goes right - and you may say, “but Arelle, mares have foals in pastures every single day the way nature intended”. However. That 5% of the time when it goes wrong, it typically goes very, very, very wrong. If you’re going to invest thousands of dollars and months of your life to get a live, healthy foal on the ground - it’s best to have access to the best medical teams possible at the last stretch should you find yourself part of the 5% crowd.