Okay, here is what I would suggest. It appears a little wood needs to be removed from the front of the inlet. That is, the area nearest the barrel. This will help close up the gap. This is typically required on most of the inlets for these rifles.
We straighten these buttplate castings, but we can only get them so good. So, if you feel it needs tweaked and you have a stout vise, don't be afraid of bending things slightly. Oftentimes you can either bend a touch or just adjust the inletting. Both can work.
As far as screw holes go, I hear complaints, but for some reason I don't seem to ever have a problem with them. A few notes... They are purposefully offset so as to pull the buttplate in the proper directions. Some look, see this and think there is an issue. Also if you do seem to have a screw that wants to pull it off center, put this one in LAST. Tighten all the others first. This typically solves problems. You can also tap the buttplate to one side slightly with a hammer or mallet. This is not to say that we might have made a mistake. If so, the holes can easily be plugged and drilled, but putting the holes in the proper locations can be a little tricky.
I hope this helps. This task is probably the most difficult part of the SMR. We machine Woodsrunner buttplates for this very reason, but it's not an option on the SMR. I've contemplated making dies to hot for the castings to more consistent shape, but this isn't easily accomplished and has it's own difficulties.