This topic is very interesting...
Our Company has us round-up the published MDA to the next 100 (510' MDA; set it to 600).
I don't agree with the 3deg descent; there are too many variables that can assure you of a missed approach (tailwind will blow your timing out the window).
Why not get on down to MDA and look for the airport until your calculated VDP? Before you say it creates an unstable approach, we have stabilized approach criteria that forbids us from descending faster than 1000fpm under 1000'AGL. Hardly an unsafe situation.....If you don't see it by your VDP then you couldn't make a stabilized approach anyway and it's time to head on to the alternate...
By the way, can anyone fly 3deg slope/700fpm and guarantee that they will be @ MDA prior to the VDP? I imagine that under the right conditions you could very well be looking @ the second half of the runway when you finally do break out...
In summary, don't waste time getting to the MDA, fly until VDP, see runway, establish 700fpm descent, land, buy the F/O dinner....simple as that.....