Very neat, and nice to have a fairly high voltage setup like that, mine is only 36V nominal so it needs pretty fat wiring to not lose a bunch of power on the way to the motor (that was the first thing I fixed, the difference was noticable, both in range and in power).

35 Kg is doable, as long as that battery doesn't run dry!

Mine really isn't pleasant if you end up without assist, it's doable but I really hate it, especially uphill. Can't wait until I have that pack ready, but I'm not going to hurry it, I'd hate for it to fail halfway or so, and that's a lot of tinkering to be done still (and a lot of welds...). But the batteries are already here, the balancer as well, I have a BMS from a scrapped pack and a good idea of what the housing should look like, if my test pack works I'm off to the races, then it is mostly straight up assembly and otherwise I'll need to re-think the way the BMS is hooked up.

I've actually pedaled without the battery but with the motor in place.

Let me tell you, the added weight is nothing... On a hub motor when you don't have a connected battery, say because the BMS tripped as you ran dry, the motor converts a signficant amount of your kinetic energy into electrical energy and then to heat. You can really feel it cogging. I could swear the two weeks I ran it without a batteris saw my thighs get significantly bigger!

Thankfully in my city there are plentiful subway stations with elevators, so when I did run dry once, I was able to pedal my bike into the subway and take it home.

You've found a nice way to add a workout I think :) Mine is simply un-driveable for any distance without support, it's not a hub motor but a mid motor and there is a whole pile of gears that are driven as well as the motor itself. It's like trying to sail with the anchor out.