I bought rebuild kits for my 1.5" Strombergs, mainly due to them spraying neat fuel into the shower of sparks from the exploding starter solenoid when I first tried to start my donor.
I too found I had a few little brass tubes/bushes left over that I couldn't replace with hand tools, so I just left the originals in place.
Although they no longer leak it was a mistake not to fully recondition them. The dyno chappie suggested that the carbs are strangling the engine's ability to rev and make power - I only got 79bhp and the engine just wouldn't rev beyond 4300rpm (although that still feels quick in a 650kg car).
I have a pair of 1.75 Strombergs awaiting fitment to address that issue, but I think a pair of properly reconditioned 1.5's would've done the job.
My advice would be: if you can, replace everything included in the rebuild kit, if you can't, pay a pro to do it.
Best of luck.