Just looking for feedback on a few questions

Just in the beginning stages of my XK150FHC restoration but moving along nicely. Body gutted and off the frame, frame on the rotisserie and stripped ready to go for blast and Powdercoat.
Car will probably see a few HPDE days, not its major use, but that’s the reason I’m upgrading to Wilwood front brakes and firming up suspension bushings and anti roll bars (will make a rear bar) and adjustable shocks. It will be a well used back roads driver and I do like as much cornering grip as I can get.
Several, some possibly stupid, questions:
A; Bother to fully weld the frame box joints? I have on past cars but they were for track use. It’s just the cost of gas and wire and my time so not a cost issue.
B: I’m sure I’ll be needing new pistons when I get to the motor. Has the 9:1 compression ratio (up from 8:1) been a problem with unleaded 91 octane? Is it a decent power adder since the cost is about the same? Motor will be all new cam timing chains and a Pertronix 123 bluetooth distributor so ignition/cam timing should be steady. I always polish and CC match the combustion chambers as I have that equipment on hand. Usually adds a CC or so from the polish, then match to the largest chamber.
C; I have the old round pad rear brakes. Does anyone have experience with getting these rebuilt? Shop referral? I am thinking about just designing a new bracket to match the existing parking brake perch but mount a Wilwood two piston caliper above it, Anyone done this? I’ll be using a new stock master cylinder but will be adding a proportioning valve.
D: Has anyone used the “direct mount” steering rack mounts in place of the rubber isolated units? If you have, did it appreciably improve steering feedback and how much additional vibration did it add to the wheel? Good or bad idea??
I have been using the search function but a lot of the information is either old or not specific to what I’m seeking. Thanks for any help or just comments ;-).