First Engine Build

Things slowed down considerably with progress on my engine. Here's where things stand at this point.
Met with the machinist last weekend and reviewed where I want to go with my engine. The block needed a .030 overbore and the crank needed .010 off the mains. Connecting rods have been refurbished with ARP bolts.
I will be going with Keith Black hypereutectic pistons and plan to keep compression around 9.5:1. Hardened valve seats are installed. Heads will get a multiangle grind along with new stainless valves. I will talk to him about port matching the heads.
I'm still trying to decide what direction to go regarding flat hydraulic lifters versus hydraulic roller lifters. I certainly appreciate benefits of going with a roller but wonder how much additional work will need to be done to the engine to go that route. I am interested in durability and longevity in this build.
I would appreciate any opinions, pros and cons, about going with a roller setup using stock heads with 273 rocker arms. How much of an issue will I have with pushrod clearance using stock heads?