maybe 2 kg of my chosen firsts and maybe some PFA's because I know I like them.
We aren't big potato eaters either (but consume quite a lot when we have the odd hoard, or two, around for BBQ in the Summer).
We grow 2kg of 1st, 2kg of 2nd, and 2kg of PFA. We start harvesting the PFA quite early (technically its a main crop, so would not normally be harvested early if you want the full weight of the crop). We particularly like the taste, but also we find it stores better than most others that we have grown, such that we no longer grow main crop at all - they are cheap as chips (sorry!) to buy at the farm gate, and the farmers have decent cold storage, whereas our self-stored ones would all be sprouting by Christmas.
We grow 4 bags (in greenhouse / conservatory) of 1st early to get some "really early"
. For these we buy 3 tubers (loose from garden centre, or a bag of 5 if not available at garden centre) of Rocket which is the fastest I know of, for the earliest bag. They get us to the point where the outdoor crop is ready for harvesting. Then the other 3 bags we use whatever 1st early variety we are growign (usually Aran Pilot).
We favour Charlotte for the 2nd early. If you have no preference, and have not tried named varieties from the supermarket, then I would suggest that you grow a little of each of whatever your allotment association will let you have (assuming they will sell you just 5 of a variety?). In terms of flavour etc. a lot depends on your soil, and how your grow them, so growing several varieties and having a family taste-test will give you a love/hate list for future years
I'm going to have to do more homework on the firsts and seconds business because It's like another language
They can all be planted on the same day, 1st, 2nd early and Maincrop just refer to the length of time from plant-to-harvest.
The speed of 1st Early means that they are normally done & dusted before any Blight arrives - another possible reason not to grow main crop.