You're past the minimum 299 skill line, so you aren't in dire need of summoning skill merits but I wouldn't rule them out still. They certainly won't hurt and provide a very nice broad increase in abilities rather than one specific area.
As for group 1 merits, no one can tell you how to spend them. Sounds like you like Pred Claws a lot (I'm in the same boat). I did 5/5 physical acc & physical atk, and it's working very well for me. I can generally do more damage with Pred Claws than folks can do with a Lv5 group 2 merit BP. I'm also frequently the only guy using Garuda on an evasive mob, where other SMNs are using Spinning Dive or merit BPs, and generally out-damage them by about 20%. On the other hand if you use a lot of magic BPs, then the magical merits can also be extremely beneficial. Group 1 merit preferences all come down to your play style, no one can tell you what will be the best universally.
As for group 2, it's been pretty well covered already by the other responses. However, I will caution you not to follow the crowds on this one. I've seen people specialize certain merit BPs for all kinds of different reasons, Geocrush for its stun effect being the only truly exceptional one relative to the others. I've heard of folks using Wind Blade because they like Garuda, Heavenly Strike or Meteor Strike because they want to improve an otherwise fairly useless avatar, Grand Fall because let's face it, it's gorgeous... and my personal favorite, Thunderstorm to utilize Lightning Threnody which is frequently cast on HNMs to boost the BLM damage output. There are reasons to justify any of them, and I won't tell you which to do, but I will say it's important to have at least one that's 5/5. Each additional level has a very high impact on the damage. Don't just spread all your merits evenly, pick at least one to build up. For me personally, I have 5/5 Thunderstorm and 1 level in every other. This gives me a nice strong endgame BP which aligns with the spells the BLMs will be casting for the sake of threnodies and magic bursts; while also giving me the ability to exploit elemental weaknesses of any kind.
____________________________Pergatory (Asura, Kupo LS) WHM99 ~ SMN99 ~ DRK99 "If you want to know me, look inside your heart." -Lao Tzu