Yep, turn the carb to where it fits best. Two thing to consider, throttle linkage and access to the needles. It's kind of a pain to get to the mix needle from the bottom, but what ever works for the aplication and the individual plane is good.

Four strokes run best with the head up, and the head to the side. Inverted is ok, but it needs to be realy warmed up before flying. I've got an O.S 52 in a Pheonix Fun Star and it is mounted with the head at 4:30 looking from the front. The engine runs just awful for a few minutes on the first run of the day. After it is warmed up well, it runs like a champ. I found that the rocker cover collected a huge load of oil that drained down from the cam area. When it was fully heated up and spun into a mist, all was good, but the first run of the day with the puddle was ugly for a few minutes.

Tune the engines when they are warmed up. Learn to tune the four stroke. They respond a bit different than a two stroke. The like big props for their size, and they like heavy props. My choice is the APC props and I kind of buck the advise of others here, if the plane will handle slow speed, use a low pitch prop. The 70 will crank a APC 13W with athority and it will let you go as slow as the wings will allow. When you need to punch it to get out of trouble, it will respond. Right now.

Put an armed guard on your wallet and check book. They are adicting. I've currently got 9 of the four strokes and love them all.

Don