well, i will risk it, becaue i even tried to find shims and i couldn't find 'em for sale.
even if i need shims in the future..i was thinking about this...
i'll be using the diagonal/horizontal screen.. lets say the lines are aligned in the focusing screen but the photograph comes out, out of focus... i know i have to either move a little bit to the left or to the right, at least i'll have a reference for "precise focusing" then i know that i have to turn it a lil left or right... it's better than the stock focusing screen!
about metering... i already do my all metering by head and by the feedback i get from bands and stuff I'm doing a pretty good job for an amateur
Again, thank you everyone for the input and i think this topic can now be closed!
Happy clicks dear pentaxian friends!