I think the reason the shift you describe is harder is that the synchro-mesh has to work harder to spin-up the 1st gear when you are moving. I have driven MT's for years and they all were this way to varying degrees, so much so that I almost never downshift into 1st over about 5 mph, but sometimes you just need to do it, and I don't think it hurts the car unless you hear the gears grind.

The HCH is actually one of the easiest shifting trannies I have ever driven. I can snap-shift from 1-2, 2-3, and 3-4 faster than almost any other car I have owned.

I once accidentally tried to shift into 1st (I meant to go to 3rd) at about 35 mph on my '82 Subaru wagon. It just plain refused to do it, I thought my tranny had busted for a second, but quickly realized the synchro-mesh had protected me nicely.

Therefore you can use the difficulty of shifting into 1st as the car giving you legitimate feedback on what it likes to do, so if I was you I would drop speed slightly to where the downshift is comfortable, shift into 1st and mash it for the high accelleration it sounds like you want. I have done this myself many times in other cars, slow down just so I could get into first and then gun it. :-)

It is also true that over 20 years ago 1st gear had no synchro-mesh on many cars (which is almost unheard of today BTW, they all have synchro in 1st), same wth reverse, you had to shift in from a dead stop only, or double clutch, but even that didn't help much, the gears would still grind if you were moving (I am not sure but I believe that some cars still do not have synchro in reverse today).

The gear ratios are really tall in the HCH MT, which is why its 0-60 times are so much worse than the CVT, so I can understand why you would want to do a 1st gear accelleration to merge with traffic in certain cases.

FYI, mph at redline (calculated, I have only verified the first two) with stock wheels/tires are:

1st: 33 (good luck downshifting into 1st over 10 mph though)
2nd: 61
3rd: 98
4th: 133 (theoretical, limited at 114 mph)
5th: 160 (theoretical, limited at 114 mph)

Anyone ever get their HCH up to 114? I have never even been close. :-)

One of the lessons I got from the above chart is that passing on two lane roads at freeway speeds is best done in 3rd gear for maximum power. I have yet to do this and don't want to as this car ain't that fast to begin with, but at least a 3rd gear move from about 60-85 mph is possible without having to upshift while you are passing. If the pass started at 45 I would downshift to second and figure I would gain more than the loss of having to upshift to 3rd mid-pass.