Those crossovers are really nice looking! Great job with those. I like how you soldered on ring terminals to connect to the binding posts. Too cool.
After I posted about the port location, I remembered your original post on this subject and Bill blessing the bottom port location. Covered with some chicken wire, you'll be good to go. Of course, a ported cab, outdoors will invariably wind up with condensation inside, but your choice of cab material takes care of that worry...as does using plexi vs. wood for the crossover bases.
You get a big thumbs-up for thinking this through so thoroughly!
As for the cab locations, the optimal placement would be where DJP suggested. At each goal line, toed inwards. HOWEVER, me being the practical person that I am, the following thoughts come to mind.
The current towers/poles/whatever where the old cabs were already have wiring run to them for speaker signals. Putting up new poles requires all the futzing around to sink poles into the ground as well as probable trenching to lay new cable. Even if you go with (and code would let you get away with) direct-bury cable (vs. conduit with cable inside), you still gotta dig at least a 2" trench 6" or so deep...for how many hundreds of feet? See what I'm getting at?
The OTops are so efficient that with the power you're going to feed them, you should have more than adequate coverage by using the original locations...AFA I can see from the photo, anyway. My two pennies.
Looking forward to more progress and pics!!
Yeah, a few more materials, but it was real quick to cut the grooves, and all that will be left is straight line cuts on the opening with a guide rather than freehanding fiddly curves . .especially on the PVC, which is quite dense.
part of the OTop build. Hats off to you for ingenuity! Really looking forward to seeing your progress.
When I work with PL it's this . .
Note to self: screw the lid on the PVC cement everytime you use the dauber. 
