it should be able to handle it.. , oil trapping shouldnt become an issue..
water slinging may be your main issue to contend with..
when these units sit horizontal, their fins are vertical, facilitating water running down to the bottom quickly as it condenses..
in a vertical install those fins will be horizontal.. the water will wantto build up between the fins.. this rectricts airflow creating a higher static air pressure for the blower, in turn the air will start slinging the water off the fins.. any front cover or pan you build should be set up to catch that water being slung so it doesnt end up on the floor..
-Christopher