I thought the Bornless Ritual was always to invoke the God self, so i don’t see any problem using it. If you summon a spirit who does than politely ask it to give you another Invocation to call it by.
Ha! I never let a little thing like that stop me, but if you want, there is a rite I kinda based the Bornless Rite that I use linked below, feel free to adapt it as needed:
You can find the original papyrus the Borless Rite is based upon using magickal sounds in Stephen Flowers’ excellent book Hermetic Magick, but it’s a lengthy lot of vowel sounds to memorise. Mine works well for me, and I know some other people on here use it as well.
Liber Samekh is quite demanding and time-consuming if you want to follow Crowley’s way, as far as I remember.
It’s an advanced ritual, and there are several versions. The official published version is not complete but initiates who are already 5=6 A.’.A.’… usually get one that serves them most (much longer and more complex). It is inspiring, but keep in mind that is only a small part of the magical system that is full of secrecy.
I hope it helps.
Good luck!