A 200 watt speaker will keep the sound coming from your amp true and not color it like a lower watt speaker. Some like the sound of the lower watt speaker and some don't. The EVM-12L 200w speaker was considered the best compliment for the Mark Series amps and some feel it is an essential part of a true Boogie tone. From his website, EJ uses Fender Deluxe Reverb combos and Marshall 50w Plexi heads with 4x12 cabinets housing 25 watt speakers. With his setup he takes advantage of all the different tonal colors provided by the combos for his clean tones and the Marshall 4x12 with low watt speakers for his dirty tones. Your setup is definitely not like EJs but you will be able to get a smooth sound from it.
I could be wrong but I believe a 1x12 cabinet will never give you the sound of a 2x12 open back combo or a 4x12 closed back cabinet. If you have a nearby music store or know other guitarists, you should your rig through their cabinets just to see how different it can sound through those cabinets. I have been combing this forum for months and its seems the overall opinion is to try as many different set ups as you can at music stores, friends gear, etc. I even met a guy in Chicago who had set up a gear conference!!! He got something like 40 guitarists all to show up with their various setups and everyone tried each others gear. He said they had Mesa, Marshall, Fender, Orange, HiWatt, Randall, Crate, you name it. I wish I had met him sooner! :wink: There is also a music store in Chicago Make'n Music that does this same thing annually.
Anyway, the best way to figure out what will work for you is to try out as many different set ups as you can. Also, trying to keep all of your settings and volume levels relatively consistent so you can have a true comparison. Equipment can have vastly different tone at different volumes. Good luck.