Buying rear rack during pandemic crisis - go real bottom, up high, or wait? As you may know from my other question, I'm putting together a bike to commute. I'm big, heavy, and roads will be paved only first half of the way.
I will need to buy a rear rack for my bike. Thanks to COVID and huge amounts of people like me, who are fed up with public transport and irresponsible people in it, the middle range of racks is unavailable, and no one knows if it ever will be. Racks are light, but big and relatively delicate so shipping costs makes it unviable to order abroad. So I'm basically left with these options:

$15 rack that's cheap, relatively weak (officially 25kg, practically less), with traditional spring luggage clamp. They are made to be universal, for huge wheel range so they have obvious weak point and screws are known to be hard on the side mounted bike bags.

$50 - $60 range. Strong (officially 40kg, practically more), but with very narrow top and no way to keep any cargo that is not designed as a bike bag mountable on the rack.

I wanted $20 - $30 range rack that has wide top with spring holder and a mount that is easy on your bags, but I'd have to wait and hope they will ever appear, keep the reasonable price, and OEM market will not buy them wholesale. So that's probably not a real option.


I'm not asking which particular kind I should choose. Or rather I do, but my main focus is how one should decide which rack to choose when the middle shelf is empty?

Addendum — typical luggage

Heavy 17&quot; laptop with charger et all
Lunch
Water and vitamin drinks
Some books or technical documentation on paper
emergency first aid kit

Things I may need to take less regularly but still often enough:

SDS Plus hammering drill
hammock, tarp and sleeping bag
Shooting range kit for blackpowder revolver, in a metal suitcase
25kg on a rear rack is already very hard to handle, especially if it’s on the top of the rack. Start leaning the bike unconsciously while standing at a red traffic light and you’ll suddenly do a very embarrassing dance trying to prevent the whole thing (+you) from toppling over. Carrying more than 25kg on a rear rack is really not a good idea. I doubt the bolts and bolt holes of the frame can survive much more. It’s also quite hard on the rear wheel, so make sure you have a sturdy rear wheel if you plan to carry this much load.
I never had a use for the spring clamp on my first rack and removed it after some time for weight savings. It’s really only useful if you quickly want to transport something small and easy to clamp, like a sweater. Even then it’s hard to keep it away from the rear wheel. I’m commuting and traveling by bike and I’m more than happy with my Ortlieb Backroller panniers (Vaude makes very similar ones). They are extremely sturdy, roomy, waterproof and quick to take on and off.
As Qwerky mentions in the comments, bungee cords are much more useful and flexible for securing things to the top of the rack. I’m actually using the detachable shoulder straps of the Ortlieb panniers for the purpose.
One more tip from experience: Tighten the rack bolts to appropriate torque and use threadlocker, they tend to come loose.