I haven't tried postersketch yet - I keep meaning to!
Here's the way I do it. I know it sound's neanderthal because it actully involves a pencil & paper. I search for my treasury items before I even open the treasury page. I write down the item numbers to 16 items. You don't even have to click on the item to pull up the full item description because if you just hover over the item the item number will show at the bottom bar on your page. Then I open treasury and just type in the numbers. I know it sounds like more work, but it is actually pretty fast & it eliminates all the clicking back & forth between tabs.
To convo, after I've saved the treasury, I copy the treasury URL from the top of the page, click on the first item in my treasury. When it brings you to the item, click contact. This way when you convo, their item URL shows up in the subject. Then in the body I type "You've been treasured!" and paste the treasury URL. Copy this body & back page to the treasury & go to the next item, click, contact, paste.
If you are interested in making treasuries with the benefits of a group but not the hassle of a team, check this out:
http://treasurychallengenonteam.blogspot.com/It's NOT a team, anyone can participate. We make one treasury a week, but you only have to do it when you want to. Most peole do it every week because it's easy & fun! We start with an "inspiration" item from one shop. Everyone makes a treasury based on & including that item. At the end of the week, the person who's item it is picks their favorite treasury. The curator of that treasury gets to provide the inspiration item for the next week from their shop.
If you happen to have the inspiration item that week you get it into well over 100 treasuries! Several have made the FP. Even if you are just a participant, you'll get into a lot of treasuries because we tag our items & feature each others shops a lot. The beauty is, you don't have to limit yourself to featuring just the shops in the group because it's NOT a team. So it won't show in your profile. So there are no rules. So you can't get rejected. SO it's just FUN! Everyone that tries it, loves it. It's a great group of people, very positive & reaffirming. My views actually noticably went up after joining this group.
Sorry this was soooo long!