hey all, I'm after some advice for my Verada's engine, sorry if any of these are silly, but I'd rather ask a few stupid questions than hurt my engine. any advice or ideas are much appreciated, thanks.

I have noticed the lower timing cover has been chewed up by the crank pulley and timing belt, is this a common occurrence? if so is there a way i can stop it doing it to another timing cover? also are they even available anymore or is there any other models with a similar cover I can use?

I'm also doing the rear main seal, and my Haynes manual states that I have to take the sump off to remove the rear main, I don't mind doing that if I have to, but is there a way to without removing the sump? I'm tempted to completely remove the engine from the car and put it on an engine stand as I already have the heads and the bolt-ons already off.

and final question, neither my Haynes manual or the factory work shop manual state the head bolts are torque to yield but I'm thinking of replacing them anyway, as they are fairly cheap, has anyone re-used their head-bolts or just get some new ones as insurance?