First off, Congarulations on your purchase. You got a nice scope and at leats 2 good eyepieces. I have the 8mm Radian and I love it. Nice long eyerelief, very important on a short focal length eyepiece. Next, I don't know where you get your canculations from but Mars will not be very big at 111x. If your looking at a 0.6 degree field, that's well over 1800 (1/2 degree) seconds of arc. Mars is only 13.4 seconds in diameter as/of 08/31 and getting smaller. That's less than 1 100th of you field. At 0.2 it will look a little bigger but you will loose details and contrast. Also, Mars is very low on the horizon and your looking through lots of atmosphere which will degrade the image. There's no way to comensate for that. There's a huge dust storm going on Mars right now so even if conditions were perfect, you'd see no details at all. Mars has been a terrible target this year. I suggest you forget about it and go for some other deep sky objects. Have you seen globular clusters M13, M92, M2, M22, M15, NGC6229. How about the double cluster in Perseus or open clusters M39, M29, M11 or the dragonfly NGC457. There are many wonderful nebulas the Omega M17, The ring M57, the Dumbell M27, the eagle M16 or the Cats eye NGC6543. Did you look at the Andomeda galaxy M31 and companions M32 and M110. Take a look at NGC253 in Sculptor, outstanding, NGC7331 and NGC7217 in Perseus are beautiful. Try not to worry about what you can't see, enjoy what you can see.
If it looks like the secondary mirror is in the way (your seeing donuts instead of stars) your out of focus. The LX200 focus knob takes many turns when changing eyepieces to focus. It's over 50 full turns from end to end. Keep turning, you'll get it. Note also, you don't want to use high magnification on most deep sky objects. The 18MM will be much better that the 4.8 on the deep sky objects.
Sounds like you did a good 2 star alignment. If it hit the Moon and Mars, your in business. Good Luck. Keep us posted.