Soundproof a party wall

I’ve done a little soundproofing, and can tell you it is somewhat involved, not only because of the materials but because any opening, including a heating duct, door seam, or the like, can allow sound to escape. This may not be an issue with a party wall.
I used mass loaded vinyl, and since I wasn’t going to tear the sheetrocked walls down to studs-- a large walk in closet, i used furring strips to mount the stuff. It is very heavy, not easy to work with and requires you to cover it with another layer since it is highly reflective. In my case, I used soundproofing blankets over the mass loaded vinyl since it wasn’t a room open to the public. It worked fine-- I did this to mute the sound of a substantial air compressor used for my tonearm. More recently I built a sound proof box for that compressor-- lining the box with a product consisting of melamine foam (basically magic eraser stuff) formed in a sandwich with a layer of mass loaded vinyl in between. The melamine functions as the absorptive layer on top of the mass loaded vinyl, but again, this isn’t something that is exposed to public view. The material was also costly, but very effective. It might pay to get a quote or two from a contractor, since they may get better pricing on some of this material.
I haven’t used the products you mention. If you are going down to studs, you can do more, and it may be more cost-effective, but more labor intensive and messy.
Good luck, let us know what you do....

Hi Guys,

I've used the Genie clip and furring strip system as described on https://www.soundstop.co.uk/soundproofing/soundproofing-walls/Genieclip-wall-solution2.php. This was used in my house in Bristol as we had a lot of noise from students next door. Now it hasn't got rid of it completely but really has made our lives so much better.We also went below the floor boards with some Rockwool insulation but be careful with this as you need the sound insulation stuff not just the thermal. This again we got from www.soundstop.co.uk   

Hi, I've had experience being put in-charged of soundproofing an event. I thought it was impossible to soundproof the area of a backyard, but I did it with these noise barrier walls. They are easy to use and aesthetically pleasing, you must try it out if you are trying to soundproof your event. It is easy to setup and their site even has support and a blog incase you need assistance. 

Soundproofing your even makes a better event, and improves your reputation. In your case, a party, you can prevent complaints of loud noises. It is also waterproof and weatherproof so you can also leave it in the rain like I did.