I've only been in 2 but here are the strategies I've noted from chat:
1. BPA: Picking the best player available can really help you in star power. Pros: You'll get the best player. Cons: It can screw you later when that position has good players but you are full and leave glaring holes at important positions.
2. Stick to your guns: Some owners come in with a strategy and refuse to deviate from it even when there are better options. Pros you get the best players you at the positions you want. Cons: It can leave you hurting in less desired positions.
3. Go with the flow: Try to predict the flow of the draft. Pros: When you are right you get a great player before a heavy run. Cons: When you are wrong you could have taken a guy that you can get 4 rounds later and miss out on important guys at other positions.
These three strategies generally apply to most drafts though sometimes all three may be used in different stages of the draft.
There is also age to consider in an allocation draft. Because all players have different ages they are in different stages of progression and have different risks and rewards.
1. Sure thing/Win now: This strategy involves selecting mostly players older than 5 years. year 6 is when allocated draft players reach their maximum potential (during the draft, this growth returns to normal during the season). Pros: These players will open with their attributes topped or nearly topped off and this will give you a huge boost on other teams with younger players who might even be better than you if only their guys were trained up. You also know exactly what you are getting, not needing to pay any attention to volatility. Cons: These guys will retire sooner giving you a bit smaller window and forcing you to retool more aggressively than guys who will have their players for a decade. They can also create salary cap trouble as long deals can become untenable. The cheapest you can get a player with is a 6 year deal, however these players won't necessarily be around 6 years. You could offer a shorter contract, but you will pay more, offer the 6 years and worry about the retirement dead cap when it happens, or take your chances resigning him as a free agent. Alternatively you can trade him to some sucker and have him make the decision.
2 Build for the future: This strategy you take guys typically under year 3. Pros: You will have these guys for a long time and their first contract will be a no brainer cheap easy 6 year deal. They'll have a longer career making it easier to fill in holes in your roster without more being created. These guys can also boom and be much better than their initial stats suggest. Cons: Where there can be boom there can be bust. Theres nothing more deflating than seeing your stud perfect rookie 1st rounder bust hard to a 70 overall. You must pay attention to volatility here and a sizable amount of luck to go your way because the younger they are the more likely what you see isn't what you get. There will be a slow period as your new young studs grow into their positions and potential that can be frustrating. Are you feeling lucky? You might end up with that 90 in the 15th round or you might end up with that 12th rounder that gets cut after training camp.
3. Balance: This method uses a balance of older players who are sure things and players you just want to take a chance on. This gives you less risk than a young draft but also less potential reward, while being more risky than sure things with slightly more chance of reward.
These are the things I've noticed from my allocation drafts. There is no right or wrong strategy they are all equal. There will be holes in your roster, don't panic, with this many people and endless variations of strategy everyone will have holes that you will need to fill in coming drafts. Weights are different for everyone depending on their playing style and their strategy. You will likely see someone take a player you rate as a 60 while there are still players you rate as a 90 on your board. This doesn't mean they made a bad pick, it means they value the players differently (okay sometimes it might be an accident or a bad AI pick). Always keep your draft board as stocked as possible, you might need a break and you'd be surprised how quick you can run out of players on your board or how tired you are from setting your board and not want to do it, this is when you make big mistakes, even resulting in terrible AI picks if you run out (common for naps and over sleeping especially in late rounds).
Allocation drafts are fun but they are taxing. This draft will set the tone for your team for the next 2 seasons minimum (All contracts are 2 or 3 years dependent on draft position) so pick carefully. Try your best and remember to have fun.