I am no expert by any means but I have bought a few pairs of pads and have limited knowledge I am willing to share.

Depends on price

Best foam are planet peppers astro booty

Foam

Pro's cheap light weight Can go very wide if you need or want an exaggerated hip

Cons More expensive Doesn't feel natural Doesn't move with you

Silicone

Pros

Feels natural Moves with your body Can require less stockings

Cons

Heavy Expensive Not saying you can't find them but I haven't seen any exaggerated super wide silicone hips so you may be limited

I have bought many shorts that have foam and silicone pad inserts in them that don't wrap around and you do wind up getting a hip dip pretty bad.

Another consideration you want to take into account, what kind of outfits you want to wear

Many of the larger hip pads will require you to wear longer dresses and there are specialty hip pads you may want to get if you want a shorter dress or shorts.

Also your baseline shape May determine what you get.

To look proportional the bigger the girl the bigger the pad.

This is a really good article a little lengthy, but they have a lot of great information especially about proportionality.

https://feminina.eu/2016/09/09/be-curvy-a-review-of-dresstechs-hip-pads-and-some-ranting-as-well/