that's would be too much, about 500mg max. in my opinion as enanthate peaks in a short time almost no more than 24hours after the shot
I would take up too 1000mg of Sustanon but not with enanthate
Technically, you could shoot 1g in the same day since it takes ~10-14 days to fully release. But the intelligent thing would be to split the dosages into two per week.