Thinking of doing a cycle of WB + SB + primal, then a cycle of LB + HS + PN.
The idea is to go back and forth between a wealthy well established power man, to the perfect lover, hopefully combining them in due time.
are there any rules for changing subs between cycles?
Only recommendations 
There’s the "recommendation " to only change one sub per cycle.
I’d guess once you’ve integrated a sub deeper there’s more leeway, but as long as you didn’t run the subs for some cycles, you might experience severe overload.
Or cheat. Two customs. Ha
Now… WB & Primal… that’s unique 
To me that sounds interesting
WB + SB + Primal
I’m running
WB + Khan + SSX (custom)
Also… your
HS + LB + PN
Rivals my
KB + ROTNW + PN (custom) 
The basic rule is to never mixed everything at once and do not listen to title/s more than what was allowed.
It’s like coffee, you put on the basic ingredients and add some secret recipes to make it unique.
MWF LB+HS, TTH WB or SB (I would prefer to listen to this once every other week) the result is much quicker than doing the three day schedule.
It is not limited to the title/s that you mentioned above.
WB+Emperor, WB+Khan1 (and the other stages but not at once)
But I would not recommend listening to LB+HS with seduction titles.