If you run a road chain, a dos eno will be just fine and chainline will not be an issue. I run a 8sp chain and a dos ENO setup and my drivetrain is very queit. 2 freewheels are fine, but a DOS ENO's outside cog will actually give you a better chance at a good chainline since it is pushed out ~2mm from the center of the FW.

Two cheap freewheels on either side also poses the problem that you will have 2 freewheels to maintain and replace. Shimano and ACS freewheels are junk. yes they work just fine, but I have had more than a few Shimanos slip on me because they are not sealed and the prawls get gunked up and worn.

The only thing you have to worry about w/ a DOS ENO is that you rear brake pads may not line up perfectly when swaping between cogs. You have the option of running a road double up front (which is what I do) and then you have two very different gears and no chainline or chain length problems.

LMK if you need measurements on the DOS to figure out your chainline. I have a 16/18 and a 16/19 sitting in my garage if you need specs.

The other added benefit is that you will likely never need another FW unless you want different gearing or you ride in muck and don't maintain your bike.

PM me if you want the 16/18. It is like new, and I never use it since I always just use my 16/19.