You need to read the bag; some lamb feeds recommend a total of 1L per day (on average) and some 1.5L, so we can't answer for you, unless you tell us which feed it is.
Lambs do drink fast, yes! You can try the smaller holes to slow them down, but sometimes that just makes them pull harder, and make their gums and lips bleed. (Silly little bleaters!

)
Drinking fast won't hurt them, provided the feed isn't too large for the first stomach, and that it goes
into the first stomach. So if you're increasing the size of feeds (because reducing number of feeds), go up over a few feeds/days to make sure you're not going to overflow the first stomach. And attend to your feeding technique - the lamb needs to have its nose above the horizontal, but ideally with the neck/front end dipped down - the same stance as it would have drinking from its mother - and, as with feeding human babies, you need to hold the bottle at an angle so that no air gets in with the milk.
If the lambs have been properly brought to this stage by someone experienced, the feeding stance shouldn't be an issue, as they'll have developed the correct reflexes for routing the milk down the oesophageal groove and into the correct stomach. It's where inexperienced people feed the lambs for the first few days, and don't get the milk routing correctly, that you are more likely to have problems with milk getting into the rumen instead of the abomasum and causing bloat or other issues.
I don't know why I wrote all that out, I should have just linked to
jaykay's excellent post on milk routing / stomach use / bloat
All ruminants should have forage (hay, straw or grass) within the first week of life, as it stimulates the rumen - which may not grow properly without this early stimulation.
Whilst I agree that you want them eating creep (mine seem to switch onto it naturally at around 3 weeks), I would never deprive a ruminant of forage.
Some of twizzel's advice, IMO, comes from the system he operates, being ad lib -> 2 large feeds -> weaning. If you're keeping them on bottles until you wean, IME you don't have the same problems. (I've never used a shepherdess, so I can't offer my own experience on that system.)