Unfortunately there won't be enough space for 4 nic shots. Also another issue would be the ratio of Nic shots will be to high as 40ml / 140ml (if adding to the full 100ml provided) will be over 25%
I myself prefer around 5mg so if you are fortunate enough to have higher level nicotine lying around you can achieve this quite easily (with say 72mg nic) as you require less ml of it
Hope that makes sense. Also in regards to promos next will be valentine's but drop me a PM and I can sort you out