In Frod's example there is there a way if I want to still use GS to do something like
/console gs c equip sets.precastbpdelay
/console gs c pact bp70 <wait 1>
/console gs c (something to initiate bprage gear logic from lua)
/console gs c (something to initiate idle logic from lua)
?
Yes, I've done something like this in my Lua if you're curious to see how it works. It's called LagMode in my Lua, and it stops the Lua from waiting for a server response when you do a BP. It just equips BP timer gear for the BP, then half a second later, equips the BP Rage/Ward gear.
https://pastebin.com/Fa5PtueC
The core of the logic is around line 678. Also, in order to make it work, I had to allow you to swap into BP gear through self_command, and that logic is around line 834. I suspect that's the main piece you're missing. Basically when your midcast fires for the BP, it queues up a self_command for half a second later to feed the name of the BP back into self_command and tell it which BP to equip gear for (for example "gs c EquipBP Volt Strike").