to decide this issue, you need to arrive at a pre-money valuation. the rationale for pre-money is this: your investors pay a
price (10k), in return they get
value (share in future profits). you need to decide what this value is on risk adjusted basis (premoney valuation).
pre-money: it's a figure which gives a hypothetical value of your startup
this figure is arrived at by calculating a probability weighted average of how much the company will be worth in case of a home run, a good outcome, an ok outcome an worst case scenario (risk adjustment)
then, you and your angels will argue this figure by shuffling term sheets backwards and forwards, until you arrive at a mutually accepted pre-money valuation
you will need to defend a higher pre-money valuation by siting a range of things including; the time you've put in to find and define this opportunity (sweat equity) and the valuations of comparable startups
post-money: then, once the pre money valuation is sorted - you can get to the gritty business of cutting up the value pie, by adding the $40k to the pre-money valuation to arrive at a post money valuation, and then deducing how much ownership $10k buys each investor at a post-money valuation.
here, you need to see a lawyer because different classes of securities will have different rights attached to them
because the angels have a different involvement than executive management - you will need to negotiate with them a package based on preference shares, so you can keep a majority holding in common stock, because it's gonna be needed for round B of financing.
Further reading:
http://del.icio.us/search/?all=term+sheet&src=moz
http://brode.net/whitepapers/cap_table.pdf
To answer your question: I cannot proceed because I don't know your pre money valuation
p.s. nice to see another aussie!