It is massive. Lol. But the other features you mentioned are nice.
The ST series are temporary on pads, you can get one that has a temp pad and a on/off switch. They are expensive but if you ever need it, worth it. I don't know why they feel like they need to charge so much for these switches.
At least the SR pad kinda clips to a pic rail by itself and doesn't need anything else. It isn't super tight, but stays in place ok. Depending on the location you can use zip ties or a ranger band to secure it a bit more.
Cloud defensive sells an overpriced mount for them as well if you want. I have no experience with it because it costs a lot more than zip ties.
I have 7" ones and depending on how they are mounted it is always too much or too little cord. They are durable though and bending them a bit to make them work hasn't broken mine yet.
Good luck and congrats on the deal. Still got a good deal!