Hey Pat, who makes your Main sail?
Fortunately for me, I have sufficient space between the bolt rope and head board to feed through a prefeeder.
I single-hand a lot, and I believe the pre-feeder definitely helps me raise the Main or at least frees up a hand. It should be acknowledged that it is not perfect. I don’t think it is possible to just stand in the cockpit and raise a bolt rope Main… unless I’m missing something. I think you absolutely have to climb up on the cabin and raise the main from the mast.
For my particular pre feeder, the luff of the sail needs to be more forward and horizontally in line with the feeder/mast. If I try raising with a lot of sail pulling from further back in the middle of the cockpit, the bolt rope will jam in the feeder. The spinlock version might handle this angle of attack better. Maybe I’ll switch back this year and give it a test.
My process is to pull the Main halyard down with one hand and while the sail is being raised I’ll keep it pressed into the mast slot/groove. After one pull to get it started and past my usual sticky spot at the beginning/head of the sail, it’ll usually just go without the hand pressing the sail into the slot and I can use both hands to raise the main. I'll pull down the main halyard and pile it forward on the deck. Once raised, I’ll pull the main halyard through the cheek block at the mast and cleat. I do it this way because there is less drag on the system while raising and occasionally, the bolt rope will jam up going into the slot (usually in the same spots too). I’ll just ease the sail back down a couple inches and help guide it in again for a pull. My Main sail is from 2019 I think (Banks Sails), and maybe a newer sail would feed a little better start to finish, but once in the groove my sail moves great. Bolt rope size is perfect. My process does sound a little clunky, but it's pretty quick.
I also want to mention that I bought too large of a main Hayward—10mm. Don’t make this mistake. 8mm would definitely feed through the lower cheek blocks a lot easier.
If you want to be able to stand in the cockpit and raise the Main, I think it has to be on slugs already sitting up on the boom.
TLDR
A pre-feeder does help, but it's not perfect, and you will have to be on standby to fix a jam.