Problem: Hot start.  This would be the biggest problem.  Park the plane on a hot day, and residual heat in the engine will boil the fuel in the hose that is firewall forward, and push fluid back up through the regulator.
Solution:  Hit the cold start button on the EC2.  Mixture full rich. If it doesn't crank in a few turns, hit the cold start button on the EC2.
 
(What a hack, using the cold start button for a hot start)  The point it to clear out the hot, pressurized fumes.  If the engine will run on the fumes, then when it does catch, expect it to run way lean and rough for thirty seconds until the fumes get blown through.  There shouldn't be much fumes there.  Only the line under the cowl will be heated.  As the fuel warms then boils, it will push the rest of the gas back toward the fuel regulator, locking the fumes in to the high part of the system which just also happens to be the hottest (the Delta sits about 9degree nose high on the ground).  As the fumes expand and move down the fuel line, it'll eventually reach the firewall penetration.  Notice the dogleg in the fuel line on the passenger side of the firewall, from low to high.  The fumes will have to push the fuel down the dogleg and all

the way back to the fuel tank to cause the pumps to vapor lock, all the while being cooled by the aluminum line.  Since trapped gases are a fairly decent insulator and any hot liquid gas would rise to the top, I'd expect they'd only reach an inch or so behind the firewall.  A hot

start will only be a problem till it uses up the fumes that can occupy

the 2ft of 1/4" tube in front of the firewall.


Ding! Ding!
Class is now in session.  I have my pen and paper in hand, ready to take notes.