I would start off with more test... This will keep levels at a higher average all the way through...
Let's say you inject every 10 days roughly the half life of enanthate.
If you start off at 750 you have to wait a few weeks for the half lives to start to stack up,, (commonly people mistake this for the test not "Kicking in" for a few weeks,, but in reality it's all the leftover half lives that are giving you more test each time...
Try this instead...
(If you inject more frequently (let's say every 7 days) values will start raising each week instead of dropping)
inject1 1500 in system 1500
inject2 1000 in system 1750 1500/2=750+1000
inject3 750 in system 1625 750/2=375+1000/2=875+750 (375+500+750)
inject4 750 in system 1562 (375+500+750)/2 = 812.5 + 750
inject5 750 in system 1531 781+750
inject6 750 in system 1516 766+750