Ok, nevermind... I got something working about 3 minutes after posting this question. I'll paste below what worked for my needs. Maybe this will help someone else, or maybe you all have a more direct method to achieve this.
#inputs to the Xpresso Node are Link (named "LayerLink") and Float (named "FieldtInfluence")
myObject = LayerLink
myTag = myObject.GetTag(1019364)
myTag.SetParameter(c4d.ID_CA_CONSTRAINT_TAG_AIM_TWEIGHT, FieldInfluence, c4d.DESCFLAGS_SET_0)
I am very uninitiated in Python, but I assume this is a very easy setup.
I have an Object in a hierarchy with a Constraint tag.
I want a Python Xpresso node where I can pipe in an Object link and a float value. I need the code to then set the "Strength" (Constraint Tag, Aim tab) to the Float value I plug in.
Can anyone spell out for me how to set this up? Thanks!