tryptophol reduction question

[n00dle]

Hey,
this page

https://www.thevespiary.org/rhodium/Rhodium/chemistry/tryptophol.html

talks about dialkyltryptamines from tryptophol. Now obviously this is a reducive amination style reaction, that reduces the tryptophol to it's aldehyde, so why does it only mention dialkyltryptamines? shouldnt it be viable with any amine, such as monoalkylamines and trialkylamines? i dont see why this synth is limited to DXT [where x is methyl, ethyl, etc.] when it could obviously be used for DPT, DIPT, and other interesting things, if one had the right legal situations.
Or does this method have something special about it that prevents this from happening?

[Rhodium]

shouldnt it be viable with any amine, such as monoalkylamines and trialkylamines?

Trialkylamines are unable to add to aldehydes as they are already fully substituted. Monoalkylamines may work to some degree, but will likely give lots of dimeric byproducts as two aldehydes are able to add to it (after the first aldehyde has added, the product itself is a secondary amine).