Honestly the only hover bombs I use is the mid one. Usually in case they jump around. I do ground for far and close. If they are over respecting the bombs and just holding crouch block I usually try to run in and apply pressure at the same time. It can be tough but it's a good idea to try and have a close ground bomb out as often as possible. Helps keep them off of you.
F21 is obviously a decent tool. F34 is honestly pretty decent too. I find its good to use against people who just blindly run in when you get bombs on the ground.
213 I feel is somewhat un talked about. They actually made it better in the last patch making it -1 on block instead of -6. Now it isn't amazing but The last hit is an overhead that causes a hkd right in front of you that gives you a free 50/50 after. I've had some success even dropping the last hit on blocking enemies and doing b3 or b1 if they catch on. 21 leaves you at like +2 on block which usually by the time they realized you dropped the last hit of 213 makes the next 50/50 much harder to react to. Once you have conditioned them with this string it can help get in their head and open them up a lot easier I've found. Gotta be careful though because the first hit is a high.
If you catch them with a random bomb you can run in and NJP, b2, 4, bomb for 21% and a bomb on the ground. Or end with f43 air grab instead of 4, bomb for 25% hkd instead.
Another note if you catch them full screen with a net you can shoot a hover bomb out and it will connect before the net times out. So off of full screen net trades you can do something like this,
Net, df2, dd2, dd2(after the first dd2 bomb explodes), d2, db3, 21 dd3, NJP, b2, 4, ground bomb. Think it does around 25%.
