Dude I do a bit of work for has a mango that has 30+ grafts on. Adds a couple every year, but a few drop and get rejected or get absorbed. The main tree was planted in the early eighties.
Big old turpentine/stringy stump rootstock, and branches going everywhere, but he keeps it trimmed at around 2m wide x 3m high.
Not very productive fruit wise at all, but a great way to store genetics for future grafting, which is all he does it for.
If your gonna have a crack I recommend using engraved aluminum or copper bands so you don't lose track of which wood is what when your pruning suckers.
He is getting on a bit now, in his early 90's and can't remember what half of the earlier ones are, just country of origin which makes marketing the fruit a hassle later when he sells on to the big city markets, due to trade mark/licensing issues.
Lots of "Thai special" "Indian special" "Philippine special" "Hawaiian special" heading down to Sydney/Brisbane markets each Christmas...
Bit off topic, but while I am talking mangoes, another old bloke I know has like a botanic garden of them, and used to do work for the DPI with their breeding program.
I reckon I have tried ~100varieties over the last couple years, and if your after a good one, you can't beat a "Bowen" or "Kensington Pride".
Best of the lot taste wise, and everyone I know that really knows mangoes agrees.
You don't need a rootstock with them either, they grow fine straight from seed. Bowens/Kensington pride are 10/10 for taste, everything else is a 6-7 at best.