Guys plz...:P
im very much aware that we can clear desert maps with teams even under 50...but that kind of gameplay is risky and has high probability of failing if you cant 'exactly' copy the video or be very accurate with your timing.

On a contrary lv'ing your units (silver+ rarity) or a few event/premium Plat or Black (if you have any)...to lv CC30 will indeed take a few days but will assure you smoother gameplay w/o the need of extreme accuracy from your side..and min chances of failiure.

I personally cleared the Oasis at CC20~30 team Around a month back (w/o guide) and failed like 3 or 4 times before i figured out the correct unit placement order.

It depends on your playing style...if you are in some kind of rush then go ahead..follow guides..and clear them at low lv's...I just recommended what i thought to be better.