May I recommend a different solution?
Contact a salon that does hair restoration work for women who have had traumatic hair loss due to medical reasons. They often do something called "integrated, bonded hair systems". These are not "wigs" in the traditional sense. These are hair systems, coupled with extensions to increase body,
These systems are attached via non-allergenic bonding methods and can be worn swimming, exercising, even sky diving for 4-6 weeks at a time. They you go in like for any other hair appointment, they redo things, cut your own hair, integrate it with the overall system, dye as necessary, and you're good to go for another 4-6 weeks.
It allows women who have suffered catastrophic hair loss to have far more normal lives. Often even lovers are unaware such a woman has an integrated hair system rather than all her own hair. The systems do not come off easily or accidentally, are worn like normal hair in the shower, pool, etc
I highly recommend investigating them. I plan to do so after my FFS. I've consulted with a hair restoration surgeon and he's going to do what he can but my loss on top is very severe so he is recommending this as a means to finish a very natural and complete look.