Yea, that's the tricky bit to put it up withou smearing. Especially with spacer as that makes 2 movable parts. I might use couple of studs to keep it aligned
I took a razor blade to bottom of block to make sure all the original gunk and stuff had gone to get a flat surface
We got two studs in each end asap, as soon as we mated with bottom of block you could tell it wanted to slide to the left or right, and as Alex said went round a torqued straight away after hand fitting all bolts,I left mine without oil in and to dry for 3 weeks though just to be sure