There are many ways to optimize gallery pages (optimize H tags, optimizing file size of images, adding short descriptions, good page titles, implementing proper tags on the image, good ux and so on). There is an excellent tutorial here. Good luck!

Organics around 15% and PPC about the same. Rough average comparing monthly totals average out compared to the summer months.

Measure both. By doing so, you will be able to see trends you may not see by doing one or the other.

See below from Azigo:

This post is a place to keep track of the sources of this info. So far I’ve only found a few numbers. Must keep digging.

• 30% of users delete cookies according comments by Jules Polenetsky on a panel at the W3C Workshop on Web Tracking and Privacy
• **40% **of users delete or block according to OpenTracker.net
• 36+% of Australian Internet users delete their third-party cookies in a month according to comScore report (2011)
• 76% of Safari users block third party cookies according to Gibson Research. Note: This is super-high because Safari is the only browser that blocks third-party cookies by default

Yes, and it's fairly common. Each of the search engine may or many not use your meta title. If the search engine deemed that another title (derived from the laning page) will match the user's intent better, they may switch it.  Since Google & Bing have different algo's, this happens. For more info see How Does Bing Choose The Title For My Web Page.

I wouldn't change a bit. I always focus on making sure a site is accessible and has an optimal site architecture first. For on-page content, I will create (or attempt to create)  a compelling user experience by offering content that helps solve an issue the prospect may have and focus on optimizing conversion. Most people underestimate how difficult and resource intensive this is to do because it takes a ton of time involved with data gathering, analysis and creating the content. So after you are 80% happy with this (because that last 20% will take as long as that 80%), begin implementing your off-page strategies and work in conjunction with a continual effort on improving and adding on-page content. A core objective is focusing on great content and earning the links, so that is why I typically start there. As you know, this is a process that never ends. Good luck!

For Google, typically between 920 and 923 pixels (or roughly 160 characters).  However, this does change periodically.

Yes, for the most part. Google wants to deliver the best results for visitors based on their search query. So if something is hidden from initial view this would impact ux and especially if it's poorly implemented (not intuitive). As you know, original and compelling copy is the best. Unfortunately in many situations, such as a large ecommerce site, it is resource intensive. It's best to avoid thin content. However, it does get ranked as you can grab a snippet and place in Google and look at the results. So yes, it's possible that Google will rank these pages with duplicate content in a hidden view.

I would advise you to tell your client to remove any hidden content and rewrite product descriptions. Depending on resources, they may/may not want to do this. If they don't, at least you made a recommendation. Good luck!

I don't think heavily. As long as the prospect can find the form easily (via menu item or small graphic), I wouldn't include one as it will take up too much valuable real estate on the home page.