Cryostat
I am not sure from the initial question if the cryostat is to be used cold or
at RT. Assume at RT . If  using at RT then probably need to adjust the slides
to compensate for the raised temperature.
Whether you use the cryostat to cut paraffin sections or not depends to a large
extent on the type of cryostat that you are using. Those with the microtome on
a inclined plane are difficult to use for paraffin and difficult to collect
sections. Many knife holders are smaller. Most chuck holders do not allow the
same degree of movement as in a regular microtome.
I would recommend that chucks with concentric grooves on them routinely have
some cross cuts made in them (even if using them for cryostat work) a this
helps prevent rotation of blocks.

Bottom line, use a regular microtome intended for paraffin work.
Barry