Actually it is very similar. When you kickstart a long-ester cycle with an oral, you have a very small amount of testosterone being released into your blood within the first couple weeks. It's better to think of it as taking the oral + low dose of test in those initial weeks.
The reason for this is that when you inject say 250mg of test e or c, it's not released into your blood right away. Let's say test e has a half life of 7 days. After the first week, half of your first injection and less than half of your second injection has been released into your blood. After the second week, you get the test being released that was released from the first two shots as well as the 2 shots you did in week 2, but it's still less than 500mg /week. It takes anywhere from 3-5 weeks to buildup to this amount.
Graphically it looks something like this (not adjusted for the fact test e/c is not 100% test by weight, assumes half life of 7 days):
View attachment 546666
(note, half life will vary slightly from person to person)
which give weekly dosages of:
week / dose
1.0000 156.9050
2.0000 328.4525
3.0000 414.2262
4.0000 457.1131
5.0000 478.5566
6.0000 489.2783
and so on
compare this to something like test p, which a shorter half life of 2-4 days (let's say 3):
View attachment 546667
giving weekly dosages of about:
week / dose
1.0000 280.0099
2.0000 456.3484
3.0000 491.3384
4.0000 498.2813
etc
you get there much faster with the shorter ester
as per your question, i don't really think there's a best or worst time to throw in the oral... you can do it at the beginning if you still want fast gains, you can do it in the middle if it's your first cycle and you want to see how you react to just test first , you can also do it at the end to finish the cycle strong... hell you can even do it the way you're suggesting if you really want to (it won't kill you)