1. Please advise of pros and cons. I am leaning towards the two EP350s.
2. If I do go with the two EP350s, one will be in a corner near the right front spkr (M60), with sub's driver pointing out from the corner at 45 degree angle. The second one will be in a corner near the right rear spkr (M22), with sub's driver parallel with rear wall. Both drivers will essentially be "pointing" to optimal listening/watching seat position (couch along back wall). I don't really have any flexibility on where to place and point the subs. My question regards the phase control - Will I set one sub to 0 and the other to 180 (I know that would be the clear recommendation if the subs were on opposite walls facing one another - mine won't quite match that type of setup)?
3. Finally, does the EP350 V3 indeed weigh slightly more than the EP500 V2 (some conflicting info online; I think the sub comparison table needs to be updated)?

Keep in mind that firing a sub at a 45 degree angle really accomplishes nothing. Freq's below around 80hz are non-directional so pointing the driver does nothing but looks cool. Think of a rock thown into a pond, the ripples travel outward from the source in all directions.

Also, corner placement will reinforce the bass freq's, however, most often this is not the best placement to get the flattest freq response, and to handle peaks and nulls in a room. You really need to experiment once you get the sub(s).

Two subs place on opposite walls will provide a flatter response across all listening positions, then just having one sub. I would watch Ian from Axiom's video on youtube, just search for Axiom Audio. If you can place one sub along the front wall, preferably away from the corners, and the second one near the back wall, that would be great. Another option is to have them on opposite side walls. However, one up front inphase with your mains is best.

Depending on your room size, one 500 might satisfy, but you will have to experiment with sub placement.

I had my ep 500 on my front wall but have recently moved it to the corner. I find the LFE during movies to be better with corner placement. However, I do have to turn the sub down a bit during some music to keep from sounding slightly boomy- (This was not as big of a deal with front placement.)

As to question 3) the EP350v3 packaged weighs 62 lbs according to the Purolator shipping label.

Yep, corner positioning will reinforce most room nodes, however, this is not always the best position overall.

Tough question. Before the v3 I would have said "get the EP500 for sure".

Can you give us a quick summary of room size and where the speakers & seating positions are located within the room ? That might help with the "better sub" vs. "better ability to control your room acoustics" tradeoff.

My wife nixed the idea of more stuff on the floor, so I can't do two subs. Thanks to those who provided advice. I hadn't considered the vertically oriented EP600, and I'm thinking I might be able to get away with it. It would be in the same line of sight as the right front M60 (of course a bit taller), but I could stress that the EP600 has a smaller footprint than the EP500!!! I'm rationalizing to myself that the add'l cost of the EP600 is justified over the dual EP350 V3s, because I would have spent a combined $250-300 more on top of the purchase price of the duals (for a hospital grade duplex outlet, surge protector, and good 4m cable). Also, I noticed that the EP500 has gone up in price about twice as much (percentage increase) as has the EP600 since they were introduced - I know that's a weird observation, but somehow it makes me feel like the EP600 is at the moment a better value. [It could also mean the EP600 hasn't sold as well.] Finally, the EP600 provides more real estate for me to admire the "free" high gloss vinyl finish!

Just so's you know, hospital grade outlets are "hospital grade" because they're harder to pull the plug out of. That's all, no more, no less.