I've actually been wanting to do a map of our unreformed Riksdag of the Estates, but I haven't found any kind of source on it anywhere, and likely won't until I go to a university.
While, as I informed you in the PM I sent you, you cannot do a map of the elections after party (as I mentioned, I tried to do that, but discovered that pinpointing individual Members of Riksdag's party affiliation is a wild goose chase), you can easily get one for the boundaries of the constituencies for the House of Peasants. They just used the härads as their constituencies, which each härad having one MR. As you mention, this was actually surprisingly balanced, far more balanced than it was for most of the time in the UK, but this wasn't by design as much as it was by accident.
The old härads' boundaries haven't really changed that much since the Viking Age, and was pretty much set in stone during the 1600s. The reason why it was balanced was that by dumb luck, the population ratios stayed pretty much static among farmers for much of Swedish history, with a minimum of immigration and emigration. People seldom moved away from where they had grown up. You didn't have that in England, and so what had once been sprawling metropolises, like Old Sarum, steadily declined into a hill with no residents, thus becoming rotten boroughs. Thus, there was never really an argument about changing the boundaries in the Riksdag, because there was no good reason to do it, and so Sweden never needed a Great Reform Act.
Though some national romantic Swedish historians like to use this to brag about that during the 18th century, Sweden was the most democratic nation in the world (I'm looking at you, Herman Lindqvist!), I would vehemently disagree and argue that the whole political machinery was simply to Byzantine and corrupt to even be considered vaguely democratic.
As far as the Burghers is concerned, that is just one big mess as for a long time the different cities could choose for themselves how to elect their representatives, then during the early 18th century they developed this very odd and complicated system of doing it, having the burghers elect electors after their particular line of business who then got to elect the representatives with the different electors having different amounts of vote after who had elected them, and the city council too had a specific say, etc., etc. Worst of all was that it was first in the late 1740s that rules were actually laid down about how many representatives a city was allowed to send, and then it was decided that with a few exceptions (Stockholm, Gothenburg and maybe (can't remember if or if not) Malmö),a city could send either one or two MRs to Stockholm.
The House of Clergy also had a democratic element to it. Much like in the UK, all bishops and archbishops were automatically members thereof, but during the 1700s it was decided that ordinary chaplains too should have representatives. Anders Chydenius, often heralded as the Father of Swedish Liberalism, was such an elected member of the House of Clergy.
As far as the House of Nobles were concerned, it looked pretty much like the old British House of Lords, with each noble family having exactly one representative. Originally they voted in bloc, oddly enough. This can be described as if in the House of Lords, first all Dukes voted and came to one opinion, then all the Marquesses voted and came to one opinion, then all the Earls, etc., and then finally, it was tallied so that there was one ducal vote, etc. and they were all weighted after their importance (the Dukes' vote would carry greater weight than the weight of the Barons' vote). This system however, was abolished in 1719, and then every member of the House of Nobles had one vote.
Gustav III noted that the extreme number of nobles Sweden had by his time was becoming ridiculously large (back in the 1500s it had been around 50, during his reign it was over 1000), and so drew up plans for massive reforms that would have made the Swedish parliament bicameral after the British model, but with additional modifications so that the House of Nobles only had 50 members, who had been elected by the noble families. But unfortunately, this plan never came to fruition because Anckarström decided to shoot Gustav III before he got around to it.
There was also at various times during the 1700s a movement to introduce a
fifth estates (because the problem was apparently that we didn't have enough estates!) that would include the influential persons who for various reasons were excluded from representation in the other estates. What prevented reform from happening wasn't really a conservative mindset. Many people recognized and acknowledged that there was something seriously wrong with the Swedish constitutional settlement. The problem was that people tended to have very fanciful and different ideas about how a new parliamentary system should look, and so it dragged on all the way till the 1850s before serious reform happened, and even then it was fairly controversial, with De Geer, the Swedish Prime Minister who managed to get it through all the estates, alienated awfully many of his political allies in doing so.
