Fix patio drainage with TOP N Bond

I have a patio problem, this is a small 10' x 5' entrance slab, poorly poured with improper drainage slope and 2 major low spots and bordered with brick. The slab is under an aluminum threshold / 3 door french door so pump jacking is not possible without removing the door. This also interferes with removing the slab and replacing without major sawing, sledging as well as cost of concrete.
My plan is to build a frame against threshold and brick sloping from from 1/2" down to 1/8" at the end/front of patio and resurface using sackrete TOP N' BOND. This should allow me to screed the slope in, trowel smooth then brush finish.

Am I being to hopefull or will this work ?

I know slope should be 1/4" per foot but threshold edge is only 1/2" water flows downhill, I hope !!

Should I fill the low spots 1st ?

Will Top n Bond work & hold in form to allow for and keep this slope ?
Are there any other products or methods that would work better ?

Read more: http://www.doityourself.com/forum/bricks-masonry-asphalt-concrete/525041-fix-patio-drainage-top-n-bond.html#ixzz31i38sVIi