Indeed, I was referring to mostly old growth redwoods, coastal redwoods in particular. Old growth Sierra redwoods are similar, and the base and limb diameter can be significantly bigger than the coastal redwoods. Above a certain level in either types of redwoods, locating a throw line's placement can be difficult in many instances. When setting an initial throw line over 150' up, I still maintain that placement can be dicey until the lead climber reaches it to make necessary adjustments. I have both 100'+ doug firs and cedars in my neighborhood, and without a direct unobstructed throw line, a multi-limb TIP with a basal anchor is almost always necessary. Using a drone to video the TIP is another way to confirm the integrity of the line placement if binoculars are inadequate, and pre-climb bounce testing to better ensure the integrity of a limb's strength is mission critical.
I also frown upon using spurs for tree work when not felling a tree, although doug firs may be the exception, given the thickness and ruggedness of the bark. Redwood bark is a bit more fragile and flaky compared to dougs, but it could likely handle spurs without inflicting too much harm to the tree, if there's no other viable alternative. Just be careful not to hit anyone if you dislodge a 12 foot long, tree foot wide and 4" thick sliver of bark, like I did on my last old-growth coastal redwood climb.