I think of Relaxed Regulation as being the Start Low Go Slow approach in the beginning and then not taking the cat all the way to the point of getting numbers in the normal range at shot time for every shot. See this:
http://binkyspage.tripod.com/SLGS.html. The idea is that you are letting your cat stay in safe numbers all the time, and the trade-off is that your cat may go up above renal threshold part of the time when the insulin is beginning to wear off.
If you feel you cannot follow Tight Regulation that is all right. It is better to admit that than to risk your cat having a hypoglycemic incident when you are not there to save her. However, I hope that the mere amount of testing is not what is holding you back from getting your cat relaxed regulated. You do have to worry about giving too little insulin as well as too much.
I agree that TR seems to be a better place to get advice than Relaxed most of the time, but there are experienced people who check in with Relaxed. Also, if you aren't getting enough answers you could post in TR when you need to like this: "Someone experienced with dosing please see my post in Relaxed." There are experienced people who will come over to help you, no doubt.
I agree with the post above: I can't understand why a vet would tell you to not test before each test and once in the middle of at least one cycle per 24 hour period. The only explanation I can think of is that your vet doesn't understand how the long acting insulin works, how to dose Lantus, and how to regulate a cat. That's a shame. You can overdose or under-dose your cat, and neither is good.
If you are the type of person who can test more than 4 times a day, that is great. If four times is all you can do, or three sometimes, that is better than nothing for sure. If you are testing only three times, I recommend that you make the 3rd test in the middle of the day cycle when you are home to do it and at night as much as possible the rest of the time. It's important to get both because some cats have very different numbers at mid-cycle in the night -- it has to do with the circadian rhythm.
If you are not going to test at mid-cycle you may want to look into using a different insulin which uses the shot time BG reading as the information to determine the dose. There are forums on this site for those users, too.
Good luck!