SWIM wonders if it is OK to reduce combined heptane pulls in a distillation setup.

She would like to save the solvent but is worried that the heat required for heptane evaporation may damage the spice. It also seems that due to reduced solvent volume and supersaturation mechanical losses will be higher.

in freebase form, it is likely spice will distill before heptane

Then, I suppose, vacuum distilling should help?

Why not use a better solvent instead, of a more complicated procedure?

Diethyl Ether, or Dichlormethane have far lower boiling points.

how would that help?
vacuum distillation is more appropriate for high boiling compounds or compounds that normally decompose rather than boil at atmospheric pressure.
dmt doesn't decompose, it simply has a lower boiling point than heptane; but heptane's boiling point isn't much higher either...heptane will most likely distill over with dmt under reduced pressure.

Most probably you are right. I thought that under vacuum heptane may evaporate at a temp lower than that of spice.

With all the speculations that Merck's boiling temp for dmt is incorrect why wouldn't somebody simply check it?

I cant tell you what the BP of DMT is exactly, but i can tell you it is far above 98C of heptane.....