Covers, yes, always a knotty problem...
I have my standard P drilled for them, but rarely put them on. The pickup cover is very wide, and doesn't make a good thumbrest. Otherwise, they are OK.
On the 51RI, they stay on permanently. The pickup cover is much narrower, and is where a thumbrest might be, level-wise. Also, the slabs look bad without them, IMHO. Splits look good either way...
And the drilling? Yup, scary. But what the hell.