Questions about bass-reflex box

I got 2 questions regarding the bass reflex enclosure :

1) First is about the construction. I want to make a double baffle, but I'm not sure how to join the 2 baffles together. Do I just glue them and use some clamps till the glue dries ? Or do I have to drill screws also ? If I have to use screws, do I screw them on the interior side of the baffle or the exterior side. If the baffle is 2 x 3/4" thick, how long should the screws be ?

2) My second question is about the tuning frequency of the box. Let's say I use speaker A and tune the box to 40 Hz. If I use speaker B (with different specs) on the same box, will it still be tuned to 40 Hz ?
 
Actually, that's more than 2 questions

1) If the two baffles are small enough. you could probably press them with concrete blocks, etc. If screwing, cut the driver holes first - one screw in the wrong place can ruin your day and your tool bit / blade. For a total thickness of 1 1/2" , 1 1/4" Lo-root or deck screws would be more than sufficient - do not use drywall screws. Which side to screw from depends on how you plan to finish / cover the boxes.

2) no
 
But isn't it the combination of driver's parameters and enclosure volume/ tuning that effects the net outcome, which in the case of subwoofers is often targeted for a very narrow operating bandwidth? So while the box may still be tuned to 40Hz, the two could sound quite different, and the second driver might not meet the design goal.