Welcome to the forum Davidtheguitarguy. This is going to be a little long - but I have a lot to say... and most of it is relevant!
I know precisely nothing about that mod, and after searching I couldn't find a user manual.
Let me give you some general info though, and a bump to the thread to see if anyone else can help.
The good news is if they are genuine AW batteries as the vendor website says they are, you have two pretty good quality batteries. You can stack 18350 batteries in an APV, if you do it safely - in fact some APV's recommend stacking batteries to allow them to output the true range of voltages and wattages of the device.
To stack safely, you need to number the batteries 1 and 2 and rotate the position of each in the mod every time you use it. Always use the batteries as a pair and charge them at the same time. Ideally, you should check their voltage as they come out of your APV and make sure they are reading the same voltage before and after charging.
I would never stack batteries in a mechanical mod though. Your device does offer some protections that a mechanical doesn't.
As for using an RDA like the tugboat on your APV, you will need to figure out what is the lowest resistance it is capable of firing - that's why I was looking for the user manual. I am guessing it probably won't be able to fire below 1 ohm anyway. So you could use a Tugboat on it, but you will have to build at higher resistances in order to have it fire on your device.
Using a Tugboat at higher resistances will not give you the full experience of it, but you can still get plenty of vapor and flavor from resistances around the 1.3-1.8 ohm mark. I started with a simple RDA building 1.5 ohm micro coils and had a great time learning while getting some good flavor and vapor from my Igo-L.
You probably will have to stick to single coil builds too though as your device won't have enough power to satisfactorily fire a dual coil build at higher resistances.