Hi,
I'm from a low-vintage area as well, and as a newer player to the format, I can say what I would like to see in a tournament.
What number of proxies is appropriate for the first of hopefully many events?
If vintage isn't player much in your area I would start by making the barrier of entry as low as possible. Most vintage decks as presented on TMD before recent restriction ran around 10 (very-)high price cards (power9, bazaars, mana drains etc.) as well as an expensive mana base in the form of multiple duals/fetches.
If Vintage isn't played very much already, then people are going to need at least the 10 proxies to even consider playing, and that probably only works in a legcay-heavy or older playgroup area where duals and fetches are already reasonably present. I would be thinking in the range of 15 to maybe even 20 proxies if vintage isn't really played much already to allow people a lot more freedom in deckbuilding and to take away a lot of the initial expenses of entry (which is usually the entire mana base for a deck). Even though you could argue that duals/fetches/forces etc. are an investment for anyone, they do help to raise the barrier for playing the format a lot, so a high number of proxies might be correct.
On the other hand, too many proxies might take away far too much from the game, so I would be careful to allow too many. Maybe it's a good idea to start with a very high number of proxies (say 25), and make it clear that every 1 or 2 months, the number of allowed proxies are going to drop until you get to a point where you can reasonably allow 10-15 proxies (which seems to be the usual amount allowed). This gives newer players a low entry barrier, a motivation to search out more staples for their collection, and gives older vintage players the knowledge that they won't be playing against altered cardboard for the rest of the tournament's existence.
What sort of enterance would you charge, and how 'high calibre' should the prizes be?
If there isn't much vintage going on already, I would keep entry cost low ($5-10 maybe?) and try to put as much of that money into vintage staples. If I would be playing right now, I would be very interested in playing relatively cheaply with a chance of winning duals/fetches/forces etc.
Also, try to make future purchases if possible. If you have to buy the prizes the day before the tournament, you are garantueed to have fewer cards to give out. If you can find cards on ebay, or get cheap deals for cards that you aren't going to be using in the upcomming event, try to get them anyway so that you have more prizes to give out during future events (this is of course, if you can come up with the money for this).
Giving out mutiple staples as prizes not only allows you more freedom in shopping around for them and keeping entry fees (and thus entry barrier) low, it also goes well with the above suggested structure of lowering the amount of proxies allowed in future events, because you're actually playing for cards that you would otherwise be inclined to get anyway. Not to mention that they are also part of their permanent collection, which makes it easier for them to enter other vintage tournaments further away from them that might not allow as many proxies.
Example: Winning a mox only gives you 1 more card you no longer need to proxy. A playset of duals gives you 4 cards you don't need to proxy, as well as having a more positive effect on the entry fee.
Any other advice you can give for a newbie trying to start people playing this awesome format?
Good atmosphere is important, including decent food/drink opportunities. Depending on the proficiency with vintage that the players in your area have, you might want to consider making it clear that people can always come to you during the weeks before a tournament to get some help with their decks. Many newer players might not think about simple alternatives to expensive cards to create decks that might be a little weaker, but still are competitive. Also, take the opportunity to playtest decks with possible tournament attendants.
You might even give out random cards to people who are playing in your tournament and are very new to the format. Giving someone with white in their deck their first balance can go a long way retaining those people. The card is cheap, and if they don't already have it, a permanent addition to their collection. Just see what you have lying around. unused, or can get by cheaply.
Cheers for listening, take care everyone.
robert.
Good luck with the tournaments!
P.S.: These are just my opinions of course, maybe someone with experience in the field of organizing such events has a completely different view than me. Also, most of this was aimed at areas where there is little vintage already, and/or few older players with extensive collections/resources. If there is a decent availability at your place, then things will probably sort themselves out more quickly, and you can always turn to the local veterans for more advise.