Ketobreath - Altoids (just a few at 2g carbs each over time, don't eat a tin a day).
Also, drink more water/pee more. Ketobreath is excess acetone that's created as part of the process of burning fat and creating ketones. The body gets rid of it via the lungs (preferentially) and urine. The more you pee out, the less goes in the breath... So not perfect, but helps reduce somewhat. Once you are closer to your weight goal, eat a bit more carbs and it goes away.
Next, is it your first time in "real" Ketosis? General consensus is it takes longer to get into Ketosis and recover from induction flu (fogginess/headaches/etc) the first time, and it's faster after that.
In re. how long to stay in ketosis, general stuff I see is to stay in till you meet your goals, then tweak diet accordingly. Just because you are down to your weight goal doesn't mean you can go back to pigging out on high carb stuff without re-gaining it.
Re. carb amounts, your body can swing in and out of ketosis depending on carbs. To be technical, it's always burning fat, but you are swinging into deeper or shallower states depending on your carb level. When you take carbs in, the body uses that preferentially for energy (over fat) and stores the extra as fat (easily replacing what is burned).
It's hard to tell how it will affect your body though. It's recommended to have less than 100 grams of carbs (the fewer the better). However, if you just got done with an intensive workout, you have more leeway to work with since the carbs are going to replace muscle glycogen first.
In terms of workouts, you'll probably continue to find them harder to do, depending on the exercise. When in ketosis, your body's not getting a large supply of carbs to replace the muscle glycogen you use. It'll create some from protein, but depending on the exercise intensity, it goes fast. A lot of athletes use something called a CKD (Cyclical Ketogenic Diet) where they carb load on weekends, and stay in Ketosis during the week. Depending on how much weight you have to lose, you may want to delay playing around with this (since it slows down your weight loss).
Other notes: Make sure and drink lots of water. Take potassium and magnesium supplements (the water will dilute them in your body). If your ketostix go deep purple (and you aren't diabetic), drink more water. It usually means you're dehydrated vs pumping out a lot of ketones. Make sure and get some limited exercise in each day to help things along. After about three to four weeks, the body is fully adjusted to use fat/ketones, and you probably won't see much on the ketostix.