I think that's mostly safe, except for a couple of things:
1. Make sure CustomOreGen is set to spawn clay blocks somewhere. (technically not "ore" gen, but still possible to mistakenly disable)
2. Last I knew, PFAA did not properly generate lapis/lazurite ore.
With PFAA installed, GregTech generates several vein types in the Nether that would normally be Overworld vein types. Also, my personal experience was that the "placer" deposits made it easy to get modest amounts of tin, iron, silver, electrum, and gold for early game, but once I got further in and wanted large quantities, it wasn't that great compared to GT ore generation - it may sometimes take a while to find a GT cassiterite vein, but once you do, it can easily contain 40-60 stacks of ore blocks.
Ok thanks for the info
I've been looking at PFAA. Does anyone know if it's safe to disable all ore gen apart from the PFAA ones?
Just tried the 1.10 version. 5.10.41. Are these graphical glitches a known issue or is it something on my end?
the trees gregtech adds are far better than normal trees, granting twice as much charcoal in the coke oven and plenty of saplings
there are some with special sap though I've not looked into them myself
Yes it is 100% Safe to disable them via Config as their Saplings will spawn as random Dungeon Loot. Do note though, that GT Rubber Trees make it much easier to get Rubber using the Coagulator, since the Sap Bag will directly contain liquid Latex, that you can scoop out using a Measuring Pot or (if you let accumulate enough Latex) a Wooden Bucket.
Also GT6 Trees have nice looking wooden Planks that go along with them, so disabling the IC2 Rubber Trees might be the better solution.
Note that the Sap Bag when used on a GT6 Rubber Tree, will give you IC2 Resin aswell, and that in a manner that isnt as tedious as planting several floating Resin Hole Logs like one does in IC2, and is even afk-able without babysitting for up to 64 Resin Items per collection of products.
Also while Willows may give you twice the Charcoal per Log, you shouldn't forget that other Trees might be larger and have way more Logs than a Willow, making the x2 Bonus slightly less relevant.
Ok thank you for the response guys. I'll do some testing and decide which way to go.
I've played GT5 for some time and am now trying GT6. I notice the new trees. Maple etc. Is it safe to disable the generation of these in the config? I assume they're not essential for anything. I'm using the standard IC2 rubber trees.