Your Timing chain, cam and valve train are the heart and lungs of your engine.
The best advice I can give you is new everything is money well spent!
You have a fresh engine, it's worth the extra money not to half ass it now!
Timing chain sets differ in quality wildly!
I've see a 'New' timing chain stretch as much a 3/4" in the first 1,000 miles.
I've see suposed 'Double Roller' timing chains turn into shrapnel in under 1,000 miles.
I've seen supposedly 'Reuseable' roller lifters loose bearings, rollers and axles in under 1,000 miles. (ask any engine builder that deals with a lot of 5.0 mustangs)
Buy your timing set and valve train set from a GOOD QUALITY MANUFACTURER.
CRANE, EDELBROCK, COMP CAMS...
Buy a MATCHED SET. Try not to get one piece here, and one piece there.
There is no such thing as a 'Reliable Used Camshaft'.
(If you purchased the camshaft, then it's not used, just seasoned)
Used lifters can only be used in the same engine, on the same camshaft lobes.
NO EXCEPTIONS. Camshaft to lifter wear patterns prevent this.
Some people may have gotten luck with some roller cams, but you can NEVER move or reuse lifters on a flat tappet camshaft.
Don't use 'Used' pushrods in new lifters. Pushrods have hardened ends, and used ones have wear patterns ground into them.
These patterns don't exist on the new lifters, so you automaticly have mismatched parts before you ever start the engine.
Roller tipped rockers are a GREAT idea.
This is a wear issue, and in some cases also a lubrication issue.
The roller tips will keep,
1. Your valve guids from wearing out as quickly, or just as important, keep them from wearing unevenly.
Rollers prevent the rocker arm from trying to drag the valve stem sideways.
2. Some engines, expecally V-8 AMC and small block Ford, have really crappy top end oiling. The roller tips are a low cost alternative to fully sealed roller bearing rocker arms.
3. Saves rebuilding and remanufacturing costs.
Roller tips keep the valve head from mushrooming, smearing, galling, elminating the need for new valves from these problems.
Also, the above, valve guides won't have near as much wear, and may not need to be completely replaced during a 'rebuild'.
(I replace them during a 'Remanufacture' anyway)
4. Smoother valve train movement will keep all the other valve train parts from going to the dogs sooner.
Sockets and fulcrums of the rocker arms, pushrods, and lifters will all benifit from a valve train that isn't working like it has sand in it.