1. Чтобы Slim не ругался на отсутствующие DSO и чтобы находил пользовательские include для custom Slim Templates,
в Slim Preferences (Slim->Preferences->Expert->Compiler) вписываем следующую строку:
shader -I%I -I[Get Env? RAT_USER_DSO] -I[Get Env? RAT_USER_INCLUDE] %f
Пример системных переменных:
В системной переменной PATH должен быть указан путь к shader.exe (%RMANTREE%\bin)

2. Шрифт и его размер в RIB и TCL boxes можно изменить в \lib\slim\bigstringui.slim

customui Big String? {
# ui things
set labelFont “helvetica -10”
set textFont “lucida -12”
set minHeight 50

3. Good news from RAT 6.5 Release Notes

RIB String “Variables”
Strings in RIB files may now contain “variables” which are expanded when the RIB is parsed by the renderer. These are references to Attributes and Options which are in scope at the time that the string is parsed. For example:

Attribute “user” “string mytexsuffix” ["daytime”]
Surface “mood_wall” “string texname” ["mood${user:mytexsuffix}.tex”]

The dollar-sign ($) in this example is the indication to the RIB parser that it should look for an expandable name. The following variable styles are allowed:
${name} all attributes, then options, are searched for “name” ("$Frame” is the current frame)
${namespace:name} attributes, then options, of the particular type are searched for “name” (e.g. "user:var")
${qualifier:namespace:name} the Attribute or Option qualifier specifies exactly which name to query (e.g. "Attribute:user:var")

Since the dollar-sign was not previously “reserved” for this use, it is possible that existing RIB files may have have strings containing it which should not be subjected to this kind of expansion. Therefore, this is an optional behavior which must be enabled by specifying the distinguished “name expansion” character in either rendermn.ini or as an Option at the top of a particular RIB file:

rendermn.ini: /prman/ribvarsubstchar $
inline in RIB: Option “rib” “string varsubst” ["$"]