To the OP: I have been reading this thread and have decided to weigh in a little. The biggest unknown is your definition of safe. Very few pilots of light twins (IMO) are really proficient in all segments of flight in a light twin.
You may be reasonably proficient in some of the segments. For example I would hope any multi pilot could from while en route put a twin down safely in VFR with one engine out. This can certainly be practiced reasonably safely. You might need to be sure you can do the VFR approach with very little chance of needing a go around. If you have got that down pat then in that particular segment I would think you could consider yourself proficient and "safe" as compared to flying a single engine. Once a month practicing this may be enough.
Since you said VFR only we will skip the instrument approach on one engine.
The first 10 seconds of the flight should be similar to a single except maintaining directional control on the ground with the loss of one engine. Again with a competent multi instructor you should be able to practice this a few times a year and know you can get the throttles closed and maintain directional control.
With the above considered I think you would be at least as safe as in a single during these segments which will be 99% of any flight. Only slightly more skill is needed than operating a HP complex single.
Now the segment that begins at +10 seconds to oh say +100 seconds. You now have 90 seconds of each flight that may be problematic. First this segment is difficult to simulate due to the inherent danger of shutting down an engine close to the ground. Yes you can go up to 3000 AGL, dirty up the plane and pull an engine. This will give you some feel for the situation. However, I can promise you no amount of training at 3000 AGL and knowing ahead of time what and when it will happen will ever make you proficient for the real thing. I can also promise you that on a +30 deg day, at 100 pounds under gross if you lose one during this 90 seconds, especially from 10 feet AGL to perhaps 500 feet AGL you will have a serious problem on your hands. Unless you can practice this in a sim (which does not exist ) a pilot can not be proficient during this segment. I know the OP said VFR only but, throw in a 200 foot ceiling. I am not familiar with the Aztec performance but in the above example it may not be flyable especially with one wind milling.
So, what is the answer? If you are comfortable with being at least as safe in the twin as in a HP complex in all of the flight segments except the 90 seconds mentioned then I think your plan is reasonable. In that 90 seconds you may have to accept that you will be no safer and perhaps less safe than in the single engine.
Take a pilot with almost 7000 hours, more than half in a twin, with about 1600 hours in make and model (PA 31-350). You are departing Denver on a 70 degree day at 100 pounds under gross. You lose one at 50 feet AGL. You do a great job of identifying the bad engine and getting it feathered. As the gear is coming up the plane settles into the ground about 200 feet past the end of the runway. BTDT, fortunately the instructor re set the sim and let me try it again. I was successful the second time getting the plane back on the ground and still being flyable. Was I proficient after the second try?
