Sounds Good,Definitely not my style or way of going about things
But I have read enough about modern witches and Wicca to see that you are off to a good start.Remember after You cast your spell it's gone,don't think about it,You can cause the energy you sent while working the trick to weaken.You send the spell to the astral
If you direct it properly,and the universe excerpts it,it's gonna be ok..If time passes and it didn't work,that's ok,do if again,a bit differently,Magick is like prayer or medicene it's not always gonna work and sometimes You need to change something around.
You could try using smaller candles. Some candles last for an hour or less, but if you don't want to wait this long snuff them out--don't blow them out--but if your spell requires chanting after the candles burn down use smaller candles. You could chant after you snuff them out, but it's whatever works best for you. Good luck. :)
A weird example but true,Bodly fluids are used in Hoodoo
One time a friend and I went into an area we call,The Weeds on a very dark winter night,it's along the highway in new york called the belt parkway,it connects along my area in Queens all the way through the beginning of Brooklyn.A small lake had frozen over
We decided to cross it,we set out for an adventure on that cold winter night and that is what we got.After walking deep enough the highway way light could hardly be sceen,it was dark
We came across a very high tree,every single branch covered on Coors bottles,several people must have worked on this as a latter had to be used.Right away we knew evil was there hence the bottle tree,a few more feet in we heard the bats next we saw them
We decited to cast a circle and do a few chants and then make our way back safely,so We urinated a circle projected from our bodies with great fear to protect us in this circle while we prayed the evil there would not harm us..Long story short,a few months later it was all over the news that the Mafia,had not only been burning bodies their since the 70s but a rat had told them where they were buried in exchange for immunity.The point is a circle can be made from anything anywhere ever out minds.
i suggest using a smaller candle. unless you want to recast the spell for several nights in a row to increase the amount of energy you put into it, you really only need one of those t-candles or slightly bigger.
regarding your spell casting process, that sounds fine. when my coven has meetings spell work comes near the end, so we normally meditate, have a ritual, give offerings, then do spells. whatever helps you connect and/or gets you in the right mindset is fine.
If you want to cast a circle around your altar, it is simply an energy circle unless you choose to make it more physical. If it is simply an energy circle then it should theoretically be able to go through walls, I know I have done circle castings through walls in the past.