Doubling my skimmer or not

I don't think its "necessary" to go double in my opinion. However i still think its a good idea to go a bit bigger then the standard recommendation. The reason being if while you are away and you have a fish or something die, the larger skimmer will be able to pick up the slack and keep your tank clean until you get back.
However if your not in the market to keep more sensitive critters such as sps corals, maybe having just a small skimmer is all you really need. Seeing as though soft corals and some species of lps appreciate more nutrient rich waters this may actually help with the overall health of the animals.
I personally have a mixed reef, travel a good deal in the summer, and i like to do water changes only maybe once every 2 or 3 weeks. My system is 83 gallons of actual water after displacement. I decided to go with the Reef Octopus NWB 150. Its rated to ~ 150 gal. Its not exactly double the rating, but plenty of extra to help me out. And i have to say, the first few months my tank was up and running, the water was way too clean to even get this thing to skim reliably. Its running great now and i would highly recommend a Reef Octopus for your system.

 

I did not turn my skimmer off at night... I dosed reef chili or phyto from time to time and turned my skimmer off for 2 hours on a feed timer. Every so often I would turn on a power head in my sump to stir up and clean out all the ditritus at night and would turn in off for a couple hours for that. All this was on timers.