I had the Vacmaster VP215 chamber sealer for about 6 weeks and have been using it quite a bit for vacuum compression and sealing up proteins for cooking sous vide. I generally buy meats in bulk, season, seal and throw in the freezer, when it's time to cook I just pull them from the freezer and put them right in the bath. Depending on the thickness of the protein I'll generally add 30-45 minutes to the total cook time and I'll usually throw it in the bath while it's still heating up.
I have been thinking about the best settings for various items and have found some resources online to point me in the right direction. Vacmaster has a chart online that gives recommended vacuum, seal and cooling times for several models of the sealers, it can be found here. For the VP215 is recommends a 30 second vacuum time for meat, fish and poultry, 20 seconds for fresh fruits and vegetables and 15 seconds for soups. Out of the box the VP215 has a default setting of 40 seconds vacuum time, for some reason mine started out at 60 seconds. The seal and cooling times depend on the thickness of the bags you're using, the chart doesn't indicate what types of bags the times are for but they're what I use for 3 mil bags. Thicker bags and bags made of other materials (like Mylar) may require adjustments to the settings.
Dave Arnold from Cooking Issues and his company Booker and Dax (Searzall, Spinzall) wrote an interesting piece back in 2009 about an experiment he did where he compared the results of vacuum sealing three different proteins ate 5 different vacuum levels with and without oil in the bag for chicken and fish and oil in the bag for all steak samples, the article can be found here. The vacuum levels he used were 90%, 98%, 99%, 99.9% and 99.9% + 15 seconds of vacuum and each vacuum level had one with and one without oil in the bag. All bags of each type of protein were cooked at the same time and temperature and in each case the one sealed at 90% vacuum with oil was the preferred product. The VP215 only allows you to set vacuum by time rather than % vacuum so I'll have to do some playing around to try and get appropriate times to achieve 90% vacuum with and without the filler plates in place.
EDIT 9/27/18: Was vacuum sealing some bacon last night to sous vide and played around with the vacuum times, with both filler plates in place it took 15 seconds to achieve ~90% vacuum. That does leave a little bit of air in the pouch so floating was an issue. The pouch sealed with 30 seconds of vacuum time looked to be 98-99% vacuum and did not need to be weighted down. I'll probably stick with 30 seconds to package meats just so I don't have to worry about them floating during the cook.
Like I said at the beginning I've been doing a lot of vacuum compressing since getting the VP215 and have really enjoyed the results with honeydew melon and watermelon. Recently someone suggest trying pineapple sealed with a little rum and it was fantastic! Next time I try it though I may add a pinch of salt to make the flavors pop. Might also be interesting to all some coconut to the mix to try and get a piña colada vibe.
