Linetype Scale

The short answer is no. You can't control the "scale" of the internal linetypes in the same way you could control custom line styles.

You CAN control their appearance on your plots. The plotted scale of internal linetypes is controlled by a section in the plot driver file that reads something like this:

; The style records defines how the design file line codes (styles)
; are to be plotted. By default, values are in plotter units (resolutions).
; Values determine pen down/up movements, where (14,42) for a dot
; pattern leaves the pen down for 14 units and up for 42 units. The
; /nohardware switch causes software stroking with these values.
; Valid units are MM, IN, or DOTS (the default)
;
style(1) = ( 0.35, 1.05) /hardware /units=MM ; style = dot
style(2) = ( 1.75, 1.05) /hardware /units=MM ; style = med dash
style(3) = ( 4.20, 1.40) /hardware /units=MM ; style = long dash
style(4) = ( 2.80, 1.05, 0.70, 1.05) /hardware /units=MM ; style = dot-dash
style(5) = ( 1.40, 1.40) /hardware /units=MM ; style = short dash
style(6) = ( 2.10, 0.70, 0.70, 0.70, 0.70, 0.70) /hardware /units=MM ; style = dash-dot-dot
style(7) = ( 2.80, 0.70, 1.40, 0.70) /hardware /units=MM ; style = long dash - short dash